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Percona Live 2012PPT： introduction-to-mysql-replication

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This document provides an overview of MySQL replication including: - Replication enables data from a master database to be replicated to one or more slave databases. - Binary logs contain all writes and schema changes on the master which are used by slaves to replicate data. - Setting up replication involves configuring the master to log binary logs, granting replication privileges, and configuring slaves to connect to the master and read binary logs from the specified position. - Commands like START SLAVE are used to control replication and SHOW SLAVE STATUS displays replication status and lag.

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Introduction To MySQL Replication Kenny Gryp <kenny.gryp@percona.com> Percona Live Washington DC / 2012-01-11
MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 2
MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 3
What is Replication? Replication enables data from one MySQL database server (the master) to be replicated to one or more MySQL database servers (the slaves) (Source: http://dev.mysql.com/doc/refman/5.5/en/replication.html) www.percona.com 4
Replication Diagram APPLICATION Queries MASTER SLAVE ... SQL Thread ... MyISAM MyISAM INNODB INNODB IO Thread BINLOGS RELAY LOGS www.percona.com 5
Replication Diagram APPLICATION Queries Queries MASTER BINLOGS SLAVE ... SQL Thread ... MyISAM MyISAM INNODB INNODB IO Thread BINLOGS RELAY LOGS www.percona.com 6
Replication Happens at MySQL level, not Storage Engine Level (*NDB) Asynchronous! (Semi-sync available in 5.5) A server can have only 1 master IO Thread: Fetches from master SQL Thread: Executes on slave Single Threaded Execution (Expect enhancements in 5.6) Different schema’s are possible between master and slave (Watch out!!): different indexes storage engines data types columns www.percona.com 7
MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 8
Binary Logs BINLOG.000001 BINLOG.index BINLOG.000002 BINLOG.000001 BINLOG.000003 BINLOG.000002 BINLOG…. BINLOG.000003 www.percona.com 9
Binary Logs Set of files Contains all writes and schema changes != REDO/Transaction log Rotated when full (Set max_binlog_size) Incrementing numbers (000001,000002,000003,...) Relay Logs are also binary logs 2 Formats: Statement Based (SBR) Row Based (RBR, since MySQL 5.1) Binary file www.percona.com 10
Binary Logs - Info Files master.info Contains IO Thread information & connection information relay.info Contains SQL Thread information www.percona.com 11
Binary Log - Formats (binlog_format) Statement Based Replication (SBR): Writes statements to binary logs, slave executes the stmts (An update stmt that changes 1 row but reads many will also do the same on the slave) Some functions are non-deterministic and cause inconsistencies: UUID(), SYSDATE(), FOUND_ROWS(), UPDATE .. LIMIT without ORDER BY... Works for NOW(): timestamp included in binary log More complete list of issues: http://dev.mysql.com/doc/refman/5.5/en/replication-features.html www.percona.com 12
Binary Log - Formats (binlog_format) Row Based Replication (RBR, since 5.1): Write row changes (larger binlogs) Check Binlog_cache_disk_use, possibly increase binlog_cache_size Does not need to parse/execute queries, just make the changes necessary Much less/different issues compared to SBR: http://dev.mysql.com/doc/refman/5.5/en/replication-rbr- usage.html Mixed: Combination of both: defaults to SBR, use RBR when necessary www.percona.com 13
Looking at Binary Log Contents mysqlbinlog SHOW BINLOG EVENTS www.percona.com 14
Example SBR > SHOW GLOBAL VARIABLES LIKE 'binlog_format'; +---------------+-----------+ | Variable_name | Value | +---------------+-----------+ | binlog_format | STATEMENT | +---------------+-----------+ 1 row in set (0.00 sec) > CREATE DATABASE replication; Query OK, 1 row affected (0.14 sec) > use replication Database changed > CREATE TABLE repl (a int) ENGINE=innodb; Query OK, 0 rows affected (0.25 sec) > INSERT INTO repl VALUES (1); Query OK, 1 row affected (0.14 sec) www.percona.com 15
Example SBR - mysqlbinlog # mysqlbinlog mysql-bin.000193 ... # at 106 #120106 15:19:13 server id 9999 end_log_pos 203 ! Query! thread_id=11 CREATE DATABASE replication /*!*/; # at 203 #120106 15:19:32 server id 9999 end_log_pos 312 ! Query! thread_id=11 ! exec_time=1! error_code=0 use replication/*!*/; SET TIMESTAMP=1325859572/*!*/; CREATE TABLE repl (a INT) ENGINE=innodb /*!*/; # at 312 #120106 15:19:55 server id 9999 end_log_pos 387 ! Query! thread_id=11 ! exec_time=0! error_code=0 SET TIMESTAMP=1325859595/*!*/; BEGIN /*!*/; # at 387 #120106 15:19:55 server id 9999 end_log_pos 484 ! Query! thread_id=11 ! exec_time=0! error_code=0 SET TIMESTAMP=1325859595/*!*/; INSERT INTO repl VALUES (1) /*!*/; # at 484 #120106 15:19:55 server id 9999 end_log_pos 511 ! Xid = 14 www.percona.com 16 COMMIT/*!*/;
> SHOW BINLOG EVENTS FROM 106G *************************** 1. row *************************** Log_name: mysql-bin.000193 Example SBR - SHOW BINLOG EVENTS Pos: 106 Event_type: Query Server_id: 1 End_log_pos: 203 Info: CREATE DATABASE replication *************************** 2. row *************************** Log_name: mysql-bin.000193 Pos: 203 Event_type: Query Server_id: 1 End_log_pos: 312 Info: use `replication`; CREATE TABLE repl (a INT) ENGINE=innodb *************************** 3. row *************************** Log_name: mysql-bin.000193 Pos: 312 Event_type: Query Server_id: 1 End_log_pos: 387 Info: BEGIN *************************** 4. row *************************** Log_name: mysql-bin.000193 Pos: 387 Event_type: Query Server_id: 1 End_log_pos: 484 Info: use `replication`; INSERT INTO repl VALUES (1) *************************** 5. row *************************** Log_name: mysql-bin.000193 Pos: 484 Event_type: Xid Server_id: 1 End_log_pos: 511 Info: COMMIT /* xid=14 */ 5 rows in set (0.00 sec) www.percona.com 17
Example RBR > SHOW GLOBAL VARIABLES LIKE 'binlog_format'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | binlog_format | ROW | +---------------+-------+ 1 row in set (0.00 sec) > CREATE DATABASE replication; Query OK, 1 row affected (0.14 sec) > use replication Database changed > CREATE TABLE repl (a int) ENGINE=innodb; Query OK, 0 rows affected (0.25 sec) > INSERT INTO repl VALUES (1); Query OK, 1 row affected (0.14 sec) www.percona.com 18
Example RBR - mysqlbinlog # mysqlbinlog mysql-bin.000193 --start-position=606 ... # at 606 #120106 15:54:54 server id 1 end_log_pos 703 ! Query! thread_id=11 ! exec_time=0! error_code=0 CREATE DATABASE replication /*!*/; # at 703 #120106 15:55:02 server id 1 end_log_pos 812 ! Query! thread_id=11 ! exec_time=0! error_code=0 use replication/*!*/; SET TIMESTAMP=1325861702/*!*/; CREATE TABLE repl (a int) ENGINE=innodb /*!*/; # at 812 ... # at 937 #120106 15:55:06 server id 1 end_log_pos 937 ! Table_map: `replication`.`repl` mapped to number 17 #120106 15:55:06 server id 1 end_log_pos 971 ! Write_rows: table id 17 flags: STMT_END_F BINLOG ' SgsHTxMBAAAAMgAAAKkDAAAAABEAAAAAAAEAC3JlcGxpY2F0aW9uAARyZXBsAAEDAAE= SgsHTxcBAAAAIgAAAMsDAAAAABEAAAAAAAEAAf/+AQAAAA== '/*!*/; # at 971 #120106 15:55:06 server id 1 end_log_pos 998 ! Xid = 34 www.percona.com 19 COMMIT/*!*/;
Example RBR - mysqlbinlog --verbose # mysqlbinlog mysql-bin.000193 --verbose --verbose ... # at 937 #120106 15:55:06 server id 1 end_log_pos 937 ! Table_map: `replication`.`repl` mapped to number 17 #120106 15:55:06 server id 1 end_log_pos 971 ! Write_rows: table id 17 flags: STMT_END_F BINLOG ' SgsHTxMBAAAAMgAAAKkDAAAAABEAAAAAAAEAC3JlcGxpY2F0aW9uAARyZXBsAAEDAAE= SgsHTxcBAAAAIgAAAMsDAAAAABEAAAAAAAEAAf/+AQAAAA== '/*!*/; ### INSERT INTO replication.repl ### SET ### @1=1 /* INT meta=0 nullable=1 is_null=0 */ # at 971 www.percona.com 20
> SHOW BINLOG EVENTS FROM 606G *************************** 1. row *************************** Log_name: mysql-bin.000193 Example RBR - SHOW BINLOG EVENTS Pos: 606 Event_type: Query Server_id: 1 End_log_pos: 703 Info: CREATE DATABASE replication *************************** 2. row *************************** Log_name: mysql-bin.000193 Pos: 703 Event_type: Query Server_id: 1 End_log_pos: 812 Info: use `replication`; CREATE TABLE repl (a int) ENGINE=innodb ... *************************** 4. row *************************** Log_name: mysql-bin.000193 Pos: 887 Event_type: Table_map Server_id: 1 End_log_pos: 937 Info: table_id: 17 (replication.repl) *************************** 5. row *************************** Log_name: mysql-bin.000193 Pos: 937 Event_type: Write_rows Server_id: 1 End_log_pos: 971 Info: table_id: 17 flags: STMT_END_F *************************** 6. row *************************** Log_name: mysql-bin.000193 Pos: 971 Event_type: Xid Server_id: 1 End_log_pos: 998 Info: COMMIT /* xid=34 */ www.percona.com 21 6 rows in set (0.00 sec)
MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 22
Setting up Replication Prerequisites Change master/slave MySQL configuration Configure Replication Start Replication/Check Status www.percona.com 23
Prerequisites No way to easily create slave with 1 command It’s required to Create/Restore consistent backup using your favorite backup tool with mysqldump, use --master-data Binlog file and position from backup should be recorded File: mysql-bin.000008 Pos: 106 www.percona.com 24
Change master/slave Configuration On the master: Enable Binary Logging: log-bin=log-bin Set A Server ID: server-id=1 On the slave: Set A Server ID: server-id=2 www.percona.com 25
Why server-id ? APPLICATION Queries Queries MASTER BINLOGS SLAVE events get ... server-id=1 SQL Thread ... MyISAM MyISAM INNODB server-id != 2 INNODB IO Thread BINLOGS RELAY LOGS server-id=1 server-id=2 www.percona.com 26
Why server-id ? APPLICATION Queries Queries MASTER server-id != 1 RELAY LOGS BINLOGS SLAVE events get server-id=2 SQL Thread IO Thread log_slave_updates log_slave_updates events get ... server-id=1 SQL Thread ... MyISAM MyISAM INNODB server-id != 2 INNODB IO Thread BINLOGS RELAY LOGS server-id=1 server-id=2 www.percona.com 27
Why server-id ? Avoid events to be written more than once replicate_same_server_id does what it says www.percona.com 28
Configure Replication On Master, add permissions: > GRANT REPLICATION SLAVE ON *.* TO ‘repl’@‘slave’ IDENTIFIED BY ‘pass’; On Slave, configure replication: > CHANGE MASTER TO MASTER_HOST=‘master’, MASTER_USER=‘repl’, MASTER_PASSWORD=‘pass’, MASTER_LOG_FILE=‘mysql-bin.000008’, MASTER_LOG_POS=106; www.percona.com 29
slave> START SLAVE; slave> SHOW SLAVE STATUSG Slave_IO_State: Waiting for master to send event IO Thread State Start Replication Master_Host: master Master_User: repl Master_Port: 3306 Connect_Retry: Master_Log_File: 60 mysql-bin.000008 IO Thread Read Up To Read_Master_Log_Pos: 254 Relay_Log_File: Relay_Log_Pos: relay-bin.000002 399 SQL Thread Read Up To Relay_Master_Log_File: mysql-bin.000008 Slave_IO_Running: Slave_SQL_Running: Yes Yes Threads Running? Replicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0 Last_Error: Skip_Counter: 0 Exec_Master_Log_Pos: 254 Relay_Log_Space: 566 Until_Condition: None Until_Log_File: Until_Log_Pos: 0 Master_SSL_Allowed: No Master_SSL_CA_File: Master_SSL_CA_Path: Master_SSL_Cert: Master_SSL_Cipher: Master_SSL_Key: Seconds_Behind_Master: Master_SSL_Verify_Server_Cert: 0 No How Far Is Slave Behind? Last_IO_Errno: 0 Last_IO_Error: Last_SQL_Errno: 0 www.percona.com 30 Last_SQL_Error:
MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 31
Commands SQL Commands Adminstrative Commands Diagnostics Commands Shell Commands mysqlbinlog www.percona.com 32
Administrative Commands Rotate binary log: FLUSH BINARY LOGS Rotate relay log: FLUSH RELAY LOGS START/STOP SLAVE IO_THREAD/SQL_THREAD Remove binary logs: PURGE MASTER LOGS TO ‘mysql-bin.000005’; PURGE MASTER LOGS BEFORE ‘2012-01-01 00:00:00’; Remove all binary logs: RESET MASTER Remove slave configuration and files: RESET SLAVE www.percona.com 33
Diagnostics Commands On Master SHOW MASTER STATUS SHOW PROCESSLIST SHOW SLAVE HOSTS SHOW BINLOG EVENTS On Slave SHOW SLAVE STATUS SHOW PROCESSLIST www.percona.com 34
On Master:SHOW MASTER STATUS Current binary log file and position: master> SHOW MASTER STATUSG *************************** 1. row *************************** File: mysql-bin.000008 Position: 254 Binlog_Do_DB: Binlog_Ignore_DB: 1 row in set (0.00 sec) www.percona.com 35
On Master: SHOW PROCESSLIST Find Connected Slaves using SHOW PROCESSLIST: master> SHOW PROCESSLISTG ... *************************** 2. row *************************** Id: 4 User: repl Host: localhost:43537 db: NULL Command: Binlog Dump Time: 1264 State: Has sent all binlog to slave; waiting for binlog to be updated Info: NULL ... www.percona.com 36
On Master: SHOW SLAVE HOSTS Shows connected slaves with their server-id: master> SHOW SLAVE HOSTS; +-----------+-----------+------+-----------+ | Server_id | Host | Port | Master_id | +-----------+-----------+------+-----------+ | 2 | slave | 3306 | 1 | +-----------+-----------+------+-----------+ 1 row in set (0.00 sec) Only works when slaves have configured: report-host, report-user, report-password, report-port www.percona.com 37
On Slave: SHOW PROCESSLIST Slave Thread Status: SLAVE> SHOW PROCESSLISTG *************************** 1. row *************************** Id: 5 User: system user Host: db: NULL Command: Connect Time: 88611 State: Waiting for master to send event Info: NULL *************************** 2. row *************************** Id: 8 User: system user Host: db: NULL Command: Connect Time: 83 State: Has read all relay log; waiting for the slave I/O thread to update it Info: NULL www.percona.com 38
MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 39
Other Common Configuration Options Filtering: binlog-%, replicate-% Don’t start replication at start: skip_slave_start Put relay log events in it’s own binary log: log_slave_updates Disallow writing on slaves: read_only Automatically remove binlogs: expire_logs_days Change binlog format: binlog_format www.percona.com 40
Filtering on Master binlog-do-db=..., binlog-ignore-db=... Warning! Different behavior between SBR and RBR: SBR: Log all statements executed if the ‘default database’ (use database) should be binlogged RBR: Log all row changes of the databases that should be binlogged www.percona.com 41
Filtering on Slave replicate-do-db= & replicate-ignore-db= Warning! Different behavior between SBR and RBR Similar to binlog-do/ignore-db replicate-do/ignore-table: Filter on table level replicate-wild-do/ignore-table: Use wildcards (%,_) to filter on table level replicate-rewrite-db=db1->db2 www.percona.com 42
MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 43
Replication Architectures Master-Slave Master-Master Multi Tiered Replication Circular Replication www.percona.com 44
Master-Slave Master Slave www.percona.com 45
Master-Slave Application Master Slave www.percona.com 45
Master-Slave Application Master Slave www.percona.com 45
Master-Slave Application Writes/Reads Master Slave www.percona.com 45
Master-Slave Application Writes/Reads Master Slave www.percona.com 45
Master-Slave Application Writes/Reads Master Reads Slave www.percona.com 45
Master-Slave Master Slave Slave Slave www.percona.com 46
Master-Slave Application Master Slave Slave Slave www.percona.com 46
Master-Slave Application Master Slave Slave Slave www.percona.com 46
Master-Slave Application Writes/Reads Master Slave Slave Slave www.percona.com 46
Master-Slave Application Writes/Reads Master Slave Slave Slave www.percona.com 46
Master-Slave Application Writes/Reads Master Reads Slave Slave Slave www.percona.com 46
Master-Slave Application Writes/Reads Master Reads Slave Slave Slave www.percona.com 46
Master-Slave Application Writes/Reads Master Reads Slave Slave Slave www.percona.com 46
Master-Slave Scaling Reads: Slaves can take reads (remember asynchronous!) Reporting/Search queries can go to separate slave Does not take resources on master ‘live-site’-slave. (‘live site’: lower response time requirements than reports) Can have other indexes, even other tables (summary tables,...) Not much benefit when too much writes Maintenance (schema changes...) Upgrade slaves first: Take slave offline SET SQL_LOG_BIN=0; <-don’t put this session queries in ALTER TABLE ...; the binary log SET SQL_LOG_BIN=1; www.percona.com 47
Master-Slave: Reporting Queries Master Slave Slave Slave www.percona.com 48
Master-Slave: Reporting Queries Application Master Slave Slave Slave www.percona.com 48
Master-Slave: Reporting Queries Application Master Slave Slave Slave www.percona.com 48
Master-Slave: Reporting Queries Application Writes/Reads Master Slave Slave Slave www.percona.com 48
Master-Slave: Reporting Queries Application Writes/Reads Master Reads Slave Slave Slave www.percona.com 48
Master-Slave: Reporting Queries Application Writes/Reads Master Reads Slave Slave Slave www.percona.com 48
Master-Slave: Reporting Queries Application Writes/Reads Master Reads Slave Slave Slave www.percona.com 48
Master-Slave: Reporting Queries Application Writes/Reads Reporting Master Reads Slave Slave Slave www.percona.com 48
Master-Slave: Reporting Queries Application Writes/Reads Reporting Master Reads Slave Slave Slave www.percona.com 48
Master-Slave: Write Intensive Master Slaves Master Slaves Capacity left for READS Capacity left for READS Capacity taken by WRITES Capacity taken by WRITES www.percona.com 49
Master-Master Master Master www.percona.com 50
Master-Master Used for: High Availability Maintenance Tasks Write to 1 master, failover to the passive master when necessary Passive master is a real slave, can be used for reads Scale Writes? NO! Every write still has to be performed on both masters Writing to both masters at the same time? NO*! Can cause inconsistencies even with auto_increment_increment/ auto_increment_offset problems can happen www.percona.com 51
Master-Master: Reads & Writes Application Writes/Reads Reads Master Master www.percona.com 52
Master-Master: Maintenance Application Writes/Reads Master Master www.percona.com 53
Master-Master: Maintenance Application Writes/Reads Master Master SET SQL_LOG_BIN=0; ALTER TABLE ...; ... SET SQL_LOG_BIN=1; www.percona.com 53
Master-Master: Maintenance Application Writes/Reads Master Master www.percona.com 53
Master-Master: Maintenance Application Writes/Reads Master Master SET SQL_LOG_BIN=0; ALTER TABLE ...; ... SET SQL_LOG_BIN=1; www.percona.com 53
Master-Master: Write to Both? Inconsistencies Application Master Master +--------+----------------+ +--------+----------------+ | userid | email | | userid | email | +--------+----------------+ +--------+----------------+ | 1 | kg@percona.com | | 1 | kg@percona.com | +--------+----------------+ +--------+----------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), UNIQUE KEY idx_email (email) ); www.percona.com 54
Master-Master: Write to Both? Inconsistencies Application UPDATE users SET email=‘kenny@percona.com’ UPDATE users SET where userid=1; email=‘gryp@percona.com’ where userid=1; Master Master +--------+----------------+ +--------+----------------+ | userid | email | | userid | email | +--------+----------------+ +--------+----------------+ | 1 | kg@percona.com | | 1 | kg@percona.com | +--------+----------------+ +--------+----------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), UNIQUE KEY idx_email (email) ); www.percona.com 54
Master-Master: Write to Both? Inconsistencies Application UPDATE users SET email=‘kenny@percona.com’ UPDATE users SET where userid=1; email=‘gryp@percona.com’ where userid=1; Master Master +--------+------------------+ +--------+-------------------+ | userid | email | | userid | email | +--------+------------------+ +--------+-------------------+ | 1 | gryp@percona.com | | 1 | kenny@percona.com | +--------+------------------+ +--------+-------------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), UNIQUE KEY idx_email (email) ); www.percona.com 54
Master-Master: Write to Both? Inconsistencies Application UPDATE users SET email=‘kenny@percona.com’ where userid=1; Master Master UPDATE users SET email=‘gryp@percona.com’ where userid=1; +--------+------------------+ +--------+-------------------+ | userid | email | | userid | email | +--------+------------------+ +--------+-------------------+ | 1 | gryp@percona.com | | 1 | kenny@percona.com | +--------+------------------+ +--------+-------------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), UNIQUE KEY idx_email (email) ); www.percona.com 54
Master-Master: Write to Both? Inconsistencies Application UPDATE users SET email=‘kenny@percona.com’ where userid=1; Master Master UPDATE users SET email=‘gryp@percona.com’ where userid=1; +--------+-------------------+ +--------+------------------+ | userid | email | | userid | email | +--------+-------------------+ +--------+------------------+ | 1 | kenny@percona.com | | 1 | gryp@percona.com | +--------+-------------------+ +--------+------------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), UNIQUE KEY idx_email (email) ); www.percona.com 54
Master-Master: Write to Both? Replication Breaks Application Master Master +--------+----------------+ +--------+----------------+ | userid | email | | userid | email | +--------+----------------+ +--------+----------------+ | 1 | kg@percona.com | | 1 | kg@percona.com | +--------+----------------+ +--------+----------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), UNIQUE KEY idx_email (email) ); www.percona.com 55
Master-Master: Write to Both? Replication Breaks Application UPDATE USERS SET email=‘legryp@percona.com’ INSERT INTO USERS WHERE userid=1; (email) VALUES (‘legryp@percona.com’) Master Master +--------+----------------+ +--------+----------------+ | userid | email | | userid | email | +--------+----------------+ +--------+----------------+ | 1 | kg@percona.com | | 1 | kg@percona.com | +--------+----------------+ +--------+----------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), UNIQUE KEY idx_email (email) ); www.percona.com 55
Master-Master: Write to Both? Replication Breaks Application UPDATE USERS SET email=‘legryp@percona.com’ INSERT INTO USERS WHERE userid=1; (email) VALUES (‘legryp@percona.com’) Master Master +--------+--------------------+ +--------+--------------------+ | userid | email | | userid | email | +--------+--------------------+ +--------+--------------------+ | 1 | kg@percona.com | | 1 | legryp@percona.com | | 2 | legryp@percona.com | +--------+--------------------+ +--------+--------------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), UNIQUE KEY idx_email (email) ); www.percona.com 55
Master-Master: Write to Both? Replication Breaks Application UPDATE USERS SET email=‘legryp@percona.com’ WHERE userid=1; Master Master INSERT INTO USERS (email) VALUES (‘legryp@percona.com’) +--------+--------------------+ +--------+--------------------+ | userid | email | | userid | email | +--------+--------------------+ +--------+--------------------+ | 1 | kg@percona.com | | 1 | legryp@percona.com | | 2 | legryp@percona.com | +--------+--------------------+ +--------+--------------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, Error 'Duplicate entry 'legryp@percona.com' email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), for key 'idx_email'' on query. Default UNIQUE KEY idx_email (email) database: 'test'. Query: 'insert into ); users(email) values ('legryp@percona.com')' www.percona.com 55
Multi Tiered Replication Master Slave Slave Slave Slave Slave www.percona.com 56
Multi Tiered Replication 2 Second query takes 6 seconds to reach the 3rd level Top level slaves could be a master for some dbs/tables too Replication main data (users...) to top level slaves Top level slaves are sort of functionally partitioned www.percona.com 57
Multi Tiered Replication: Delay Master Slave Slave Slave Slave Slave www.percona.com 58
Multi Tiered Replication: Delay Master 2 Seconds Slave Slave Slave Slave Slave www.percona.com 58
Multi Tiered Replication: Delay Master 2 Seconds 2 Seconds Slave Slave Slave Slave Slave www.percona.com 58
Multi Tiered Replication: Delay Master 2 Seconds 2 Seconds Slave Slave Slave 2 Seconds Slave Slave www.percona.com 58
Multi Tiered Replication: Top Level Slaves MASTER Master MASTER SEARCH LOG Slave Slave Slave SEARCH SEARCH Slave Slave www.percona.com 59
Multi Tiered Replication Master Slave Slave Slave Slave Slave No Updates Anymore www.percona.com 60
Circular Replication Master Master Master Master www.percona.com 61
Circular Replication Master Master Master Master www.percona.com 62
Circular Replication Master Master Master Master www.percona.com 63
MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 64
Common Issues Replication Lag Replication Breaking Crash Safe Replication Consistency www.percona.com 65
Replication Lag - Causes Single threaded execution on slave!!! Long running queries with SBR: will take ~same time on slave Many row changes with RBR MyISAM & table level locking: Long running SELECT on slave might block replication Schema changes: 20min on master, 20min on slave <-- 20 min replication lag www.percona.com 66
Replication Lag - Tips 1 Optimize DML Statements Avoid DDL Statements in Replication (SQL_LOG_BIN=0) Hardware specifications usually need to be equal or better on slave MySQL 5.6: http://d2-systems.blogspot.com/2011/04/mysql-56x-feature-preview-multi.html Ensure BBU&Write Back Cache is used or lower durability: innodb_flush_log_at_trx_commit=2 Change architecture: functional/horizontal partitioning www.percona.com 67
Replication Lag - Tips 2 Try to avoid SQL Thread to need to do disk I/O: Replication Booster (Yoshinori Matsunobu) prefetches relay logs and converts queries to select and runs them, causing data to be cached before SQL thread reaches innodb_fake_changes http://www.percona.com/doc/percona-server/5.5/management/ innodb_fake_changes.html http://dom.as/2011/12/03/replication-prefetching/ www.percona.com 68
Replication Booster http://yoshinorimatsunobu.blogspot.com/2011/10/making-slave-pre-fetching-work-better.html www.percona.com 69
Replication Breaking - Examples Last_Errno: 1146 Last_Error: Error 'Table 'db.table' doesn't exist' on query. Default database: 'userdb'. Query: '...' Last_Errno: 1062 Last_Error: Error 'Duplicate entry '1748099' for key 1' on query. Default database: 'db'. Query: 'INSERT INTO table (url) VALUES(‘http://www.google.com')' Last_Errno: 1053 Last_Error: Query partially completed on the master (error on master: 1053) and was aborted. There is a chance that your master is inconsistent at this point. If you are sure that your master is ok, run this query manually on the slave and then restart the slave with SET GLOBAL SQL_SLAVE_SKIP_COUNTER=1; START SLAVE; . Query: ALTER TABLE ‘users’ ADD ‘name’ VARCHAR(128) NULL DEFAULT; www.percona.com 70
Replication Breaking - Causes Writes happening on Slaves SBR with bad statements Crashes: Relay Log Corruption Different schemas Temporary tables Mixing MyISAM with InnoDB Different behavior between MySQL versions (minor/major) Killing queries that change MyISAM tables will be partially executed, and break replication ... www.percona.com 71
Replication Breaking - Fixing Questions to ask yourself: Why? Where? Impact? Quick ‘fix’: SET GLOBAL SQL_SLAVE_SKIP_COUNTER=1; START SLAVE; Causes 1 event to be skipped Causes inconsistencies!!! Look at: Check error & Investigate data on master/slave MySQL errorlogs SHOW SLAVE STATUSG mysqlbinlog on relaylogs/binarylogs and investigate pt-slave-restart More On: http://www.percona.com/files/presentations/percona-live/london-2011/ PLUK2011-diagnosing-and-fixing-mysql-replication.pdf www.percona.com 72
Crash Safe Replication On master: sync_binlog=1 to fsync at every binlog write Performance impact, mainly on: Ext3 filesystem http://www.mysqlperformanceblog.com/2009/01/21/beware-ext3-and-sync-binlog-do-not-play-well-together/ High write-response time disksubsystem (no WriteBackCache& BBU) On slave: relay-log.info/master.info: not durable/consistent! When OS crash, old information might be in the file If InnoDB only: use innodb_overwrite_relay_log_info in Percona Server: http://www.percona.com/doc/percona-server/5.5/reliability/ innodb_recovery_update_relay_log.html www.percona.com 73
Consistency Replication can cause inconsistencies: Statement Based Replication Certain functions like UUID()... UPDATE/DELETE with LIMIT without ORDER BY unique key Writing to multiple masters Writing to slaves (by accident? use read_only) Failover done wrong MyISAM with killing queries and/ord MySQL Crashes Wrongly restored slaves Replication broke and used SQL_SLAVE_SKIP_COUNTER ... How to know if my data is consistent? www.percona.com 74
Consistency Checking Consistency: pt-table-checksum Checksums chunks of data on master and slaves Monitors replication lag Low checksum response time to lower impact on production Uses Replication to ensure consistent view of data Fixing Consistency: pt-table-sync Can checksum and use pt-table-checksum results Fixes inconsistencies www.percona.com 75
MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 76
Replication Use Cases Scale Reads High Availability Backups www.percona.com 77
High Availability Failover: Virtual IPs Change IP in application servers Warning: Split-Brain possible!!! Ensure no writes happen on old master before moving Make sure new master is in sync Scripts available to automate failover: MySQL-MHA http://code.google.com/p/mysql-master-ha/ MMM (not-recommended) http://mysql-mmm.org/ Percona-PRM http://www.mysqlperformanceblog.com/2011/11/29/percona-replication-manager-a- solution-for-mysql-high-availability-with-replication-using-pacemaker/ www.percona.com 78
High Availability Due to asynchronous’ness, data might be lost: Semi-Synchronous Replication: ensure at least one slave’s IO thread has received the event before the transaction is committed. http://dev.mysql.com/doc/refman/5.5/en/replication-semisync.html www.percona.com 79
Backups Point In Time Recovery, using binary logs Delayed slave Backup Slaves www.percona.com 80
Incremental / Point In Time Recovery Restore Full Backup from your favorite backup tool Replay binary logs with mysqldump from the last position of the backup # mysqlbinlog --start-position=15115 1sbinarylog | mysql # mysqlbinlog next-binary-logs | mysql If PITR, stop at the desired position/time: # mysqlbinlog --stop-position=102151 binarylog | mysql # mysqlbinlog --stop-datetime=“2012-01-01 23:00:00” lastbinarylog | mysql www.percona.com 81
Delayed Slave Deliberately lag a slave for a predefined amount of time Decrease recovery time in case of bad changes caused by: Humans (DROP DATABASE) Application (DELETE FROM table;) How to configure: pt-slave-delay --delay 60m (http://www.percona.com/doc/percona-toolkit/2.0/pt-slave-delay.html) 5.6 Built-in feature: > CHANGE MASTER TO MASTER_DELAY=3600; When a problem happens stop replication just before the malicious statement. START SLAVE UNTIL MASTER_LOG_FILE='log_name', MASTER_LOG_POS = pos; www.percona.com 82
Backup using Slaves Online Backups might not be possible on active master: Too much impact to make online: InnoDB backup (using MySQL enterprise backup or XtraBackup) LVM Snapshots MyISAM tables Offsite Backup www.percona.com 83
MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 84
Other Replication Implementations Tungsten Replicator Uses binary log Parallel replication Enhanced filtering Multi-master Replication between different databases Galera Cluster Does not use binary log Synchronous replication Active-active master Parallel replication Percona XtraDB Cluster! http://www.mysqlperformanceblog.com/2012/01/09/ announcement-of-percona-xtradb-cluster-alpha-release/ www.percona.com 85
Tungsten Replicator http://continuent.com/ http://code.google.com/p/tungsten-replicator/ www.percona.com 86
Galera Cluster http://codership.com/ www.percona.com 87
MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 88
Tools & More Info Percona Toolkit http://www.percona.com/software/percona-toolkit/ pt-slave-find, pt-table-checksum, pt-table-sync, pt-slave-delay, pt-slave-restart, pt-heartbeat Percona Server http://www.percona.com/software/percona-server/ OpenArk kit http://code.openark.org/forge/openark-kit Replication Booster https://github.com/yoshinorim/replication-booster-for-mysql High Availability MMM http://mysql-mmm.org/ Percona-PRM http://www.mysqlperformanceblog.com/2011/11/29/percona-replication-manager-a- solution-for-mysql-high-availability-with-replication-using-pacemaker/ MySQL-MHA http://code.google.com/p/mysql-master-ha/ High Performance MySQL, 2nd Edition: http://shop.oreilly.com/product/9780596101718.do www.percona.com 89
MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 90
Kenny Gryp <kenny.gryp@percona.com> @gryp We're Hiring! www.percona.com/about-us/careers/

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Percona Live 2012PPT： introduction-to-mysql-replication

  • 1. Introduction To MySQL Replication Kenny Gryp <[email protected]> Percona Live Washington DC / 2012-01-11
  • 2. MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 2
  • 3. MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 3
  • 4. What is Replication? Replication enables data from one MySQL database server (the master) to be replicated to one or more MySQL database servers (the slaves) (Source: http://dev.mysql.com/doc/refman/5.5/en/replication.html) www.percona.com 4
  • 5. Replication Diagram APPLICATION Queries MASTER SLAVE ... SQL Thread ... MyISAM MyISAM INNODB INNODB IO Thread BINLOGS RELAY LOGS www.percona.com 5
  • 6. Replication Diagram APPLICATION Queries Queries MASTER BINLOGS SLAVE ... SQL Thread ... MyISAM MyISAM INNODB INNODB IO Thread BINLOGS RELAY LOGS www.percona.com 6
  • 7. Replication Happens at MySQL level, not Storage Engine Level (*NDB) Asynchronous! (Semi-sync available in 5.5) A server can have only 1 master IO Thread: Fetches from master SQL Thread: Executes on slave Single Threaded Execution (Expect enhancements in 5.6) Different schema’s are possible between master and slave (Watch out!!): different indexes storage engines data types columns www.percona.com 7
  • 8. MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 8
  • 9. Binary Logs BINLOG.000001 BINLOG.index BINLOG.000002 BINLOG.000001 BINLOG.000003 BINLOG.000002 BINLOG…. BINLOG.000003 www.percona.com 9
  • 10. Binary Logs Set of files Contains all writes and schema changes != REDO/Transaction log Rotated when full (Set max_binlog_size) Incrementing numbers (000001,000002,000003,...) Relay Logs are also binary logs 2 Formats: Statement Based (SBR) Row Based (RBR, since MySQL 5.1) Binary file www.percona.com 10
  • 11. Binary Logs - Info Files master.info Contains IO Thread information & connection information relay.info Contains SQL Thread information www.percona.com 11
  • 12. Binary Log - Formats (binlog_format) Statement Based Replication (SBR): Writes statements to binary logs, slave executes the stmts (An update stmt that changes 1 row but reads many will also do the same on the slave) Some functions are non-deterministic and cause inconsistencies: UUID(), SYSDATE(), FOUND_ROWS(), UPDATE .. LIMIT without ORDER BY... Works for NOW(): timestamp included in binary log More complete list of issues: http://dev.mysql.com/doc/refman/5.5/en/replication-features.html www.percona.com 12
  • 13. Binary Log - Formats (binlog_format) Row Based Replication (RBR, since 5.1): Write row changes (larger binlogs) Check Binlog_cache_disk_use, possibly increase binlog_cache_size Does not need to parse/execute queries, just make the changes necessary Much less/different issues compared to SBR: http://dev.mysql.com/doc/refman/5.5/en/replication-rbr- usage.html Mixed: Combination of both: defaults to SBR, use RBR when necessary www.percona.com 13
  • 14. Looking at Binary Log Contents mysqlbinlog SHOW BINLOG EVENTS www.percona.com 14
  • 15. Example SBR > SHOW GLOBAL VARIABLES LIKE 'binlog_format'; +---------------+-----------+ | Variable_name | Value | +---------------+-----------+ | binlog_format | STATEMENT | +---------------+-----------+ 1 row in set (0.00 sec) > CREATE DATABASE replication; Query OK, 1 row affected (0.14 sec) > use replication Database changed > CREATE TABLE repl (a int) ENGINE=innodb; Query OK, 0 rows affected (0.25 sec) > INSERT INTO repl VALUES (1); Query OK, 1 row affected (0.14 sec) www.percona.com 15
  • 16. Example SBR - mysqlbinlog # mysqlbinlog mysql-bin.000193 ... # at 106 #120106 15:19:13 server id 9999 end_log_pos 203 ! Query! thread_id=11 CREATE DATABASE replication /*!*/; # at 203 #120106 15:19:32 server id 9999 end_log_pos 312 ! Query! thread_id=11 ! exec_time=1! error_code=0 use replication/*!*/; SET TIMESTAMP=1325859572/*!*/; CREATE TABLE repl (a INT) ENGINE=innodb /*!*/; # at 312 #120106 15:19:55 server id 9999 end_log_pos 387 ! Query! thread_id=11 ! exec_time=0! error_code=0 SET TIMESTAMP=1325859595/*!*/; BEGIN /*!*/; # at 387 #120106 15:19:55 server id 9999 end_log_pos 484 ! Query! thread_id=11 ! exec_time=0! error_code=0 SET TIMESTAMP=1325859595/*!*/; INSERT INTO repl VALUES (1) /*!*/; # at 484 #120106 15:19:55 server id 9999 end_log_pos 511 ! Xid = 14 www.percona.com 16 COMMIT/*!*/;
  • 17. > SHOW BINLOG EVENTS FROM 106G *************************** 1. row *************************** Log_name: mysql-bin.000193 Example SBR - SHOW BINLOG EVENTS Pos: 106 Event_type: Query Server_id: 1 End_log_pos: 203 Info: CREATE DATABASE replication *************************** 2. row *************************** Log_name: mysql-bin.000193 Pos: 203 Event_type: Query Server_id: 1 End_log_pos: 312 Info: use `replication`; CREATE TABLE repl (a INT) ENGINE=innodb *************************** 3. row *************************** Log_name: mysql-bin.000193 Pos: 312 Event_type: Query Server_id: 1 End_log_pos: 387 Info: BEGIN *************************** 4. row *************************** Log_name: mysql-bin.000193 Pos: 387 Event_type: Query Server_id: 1 End_log_pos: 484 Info: use `replication`; INSERT INTO repl VALUES (1) *************************** 5. row *************************** Log_name: mysql-bin.000193 Pos: 484 Event_type: Xid Server_id: 1 End_log_pos: 511 Info: COMMIT /* xid=14 */ 5 rows in set (0.00 sec) www.percona.com 17
  • 18. Example RBR > SHOW GLOBAL VARIABLES LIKE 'binlog_format'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | binlog_format | ROW | +---------------+-------+ 1 row in set (0.00 sec) > CREATE DATABASE replication; Query OK, 1 row affected (0.14 sec) > use replication Database changed > CREATE TABLE repl (a int) ENGINE=innodb; Query OK, 0 rows affected (0.25 sec) > INSERT INTO repl VALUES (1); Query OK, 1 row affected (0.14 sec) www.percona.com 18
  • 19. Example RBR - mysqlbinlog # mysqlbinlog mysql-bin.000193 --start-position=606 ... # at 606 #120106 15:54:54 server id 1 end_log_pos 703 ! Query! thread_id=11 ! exec_time=0! error_code=0 CREATE DATABASE replication /*!*/; # at 703 #120106 15:55:02 server id 1 end_log_pos 812 ! Query! thread_id=11 ! exec_time=0! error_code=0 use replication/*!*/; SET TIMESTAMP=1325861702/*!*/; CREATE TABLE repl (a int) ENGINE=innodb /*!*/; # at 812 ... # at 937 #120106 15:55:06 server id 1 end_log_pos 937 ! Table_map: `replication`.`repl` mapped to number 17 #120106 15:55:06 server id 1 end_log_pos 971 ! Write_rows: table id 17 flags: STMT_END_F BINLOG ' SgsHTxMBAAAAMgAAAKkDAAAAABEAAAAAAAEAC3JlcGxpY2F0aW9uAARyZXBsAAEDAAE= SgsHTxcBAAAAIgAAAMsDAAAAABEAAAAAAAEAAf/+AQAAAA== '/*!*/; # at 971 #120106 15:55:06 server id 1 end_log_pos 998 ! Xid = 34 www.percona.com 19 COMMIT/*!*/;
  • 20. Example RBR - mysqlbinlog --verbose # mysqlbinlog mysql-bin.000193 --verbose --verbose ... # at 937 #120106 15:55:06 server id 1 end_log_pos 937 ! Table_map: `replication`.`repl` mapped to number 17 #120106 15:55:06 server id 1 end_log_pos 971 ! Write_rows: table id 17 flags: STMT_END_F BINLOG ' SgsHTxMBAAAAMgAAAKkDAAAAABEAAAAAAAEAC3JlcGxpY2F0aW9uAARyZXBsAAEDAAE= SgsHTxcBAAAAIgAAAMsDAAAAABEAAAAAAAEAAf/+AQAAAA== '/*!*/; ### INSERT INTO replication.repl ### SET ### @1=1 /* INT meta=0 nullable=1 is_null=0 */ # at 971 www.percona.com 20
  • 21. > SHOW BINLOG EVENTS FROM 606G *************************** 1. row *************************** Log_name: mysql-bin.000193 Example RBR - SHOW BINLOG EVENTS Pos: 606 Event_type: Query Server_id: 1 End_log_pos: 703 Info: CREATE DATABASE replication *************************** 2. row *************************** Log_name: mysql-bin.000193 Pos: 703 Event_type: Query Server_id: 1 End_log_pos: 812 Info: use `replication`; CREATE TABLE repl (a int) ENGINE=innodb ... *************************** 4. row *************************** Log_name: mysql-bin.000193 Pos: 887 Event_type: Table_map Server_id: 1 End_log_pos: 937 Info: table_id: 17 (replication.repl) *************************** 5. row *************************** Log_name: mysql-bin.000193 Pos: 937 Event_type: Write_rows Server_id: 1 End_log_pos: 971 Info: table_id: 17 flags: STMT_END_F *************************** 6. row *************************** Log_name: mysql-bin.000193 Pos: 971 Event_type: Xid Server_id: 1 End_log_pos: 998 Info: COMMIT /* xid=34 */ www.percona.com 21 6 rows in set (0.00 sec)
  • 22. MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 22
  • 23. Setting up Replication Prerequisites Change master/slave MySQL configuration Configure Replication Start Replication/Check Status www.percona.com 23
  • 24. Prerequisites No way to easily create slave with 1 command It’s required to Create/Restore consistent backup using your favorite backup tool with mysqldump, use --master-data Binlog file and position from backup should be recorded File: mysql-bin.000008 Pos: 106 www.percona.com 24
  • 25. Change master/slave Configuration On the master: Enable Binary Logging: log-bin=log-bin Set A Server ID: server-id=1 On the slave: Set A Server ID: server-id=2 www.percona.com 25
  • 26. Why server-id ? APPLICATION Queries Queries MASTER BINLOGS SLAVE events get ... server-id=1 SQL Thread ... MyISAM MyISAM INNODB server-id != 2 INNODB IO Thread BINLOGS RELAY LOGS server-id=1 server-id=2 www.percona.com 26
  • 27. Why server-id ? APPLICATION Queries Queries MASTER server-id != 1 RELAY LOGS BINLOGS SLAVE events get server-id=2 SQL Thread IO Thread log_slave_updates log_slave_updates events get ... server-id=1 SQL Thread ... MyISAM MyISAM INNODB server-id != 2 INNODB IO Thread BINLOGS RELAY LOGS server-id=1 server-id=2 www.percona.com 27
  • 28. Why server-id ? Avoid events to be written more than once replicate_same_server_id does what it says www.percona.com 28
  • 29. Configure Replication On Master, add permissions: > GRANT REPLICATION SLAVE ON *.* TO ‘repl’@‘slave’ IDENTIFIED BY ‘pass’; On Slave, configure replication: > CHANGE MASTER TO MASTER_HOST=‘master’, MASTER_USER=‘repl’, MASTER_PASSWORD=‘pass’, MASTER_LOG_FILE=‘mysql-bin.000008’, MASTER_LOG_POS=106; www.percona.com 29
  • 30. slave> START SLAVE; slave> SHOW SLAVE STATUSG Slave_IO_State: Waiting for master to send event IO Thread State Start Replication Master_Host: master Master_User: repl Master_Port: 3306 Connect_Retry: Master_Log_File: 60 mysql-bin.000008 IO Thread Read Up To Read_Master_Log_Pos: 254 Relay_Log_File: Relay_Log_Pos: relay-bin.000002 399 SQL Thread Read Up To Relay_Master_Log_File: mysql-bin.000008 Slave_IO_Running: Slave_SQL_Running: Yes Yes Threads Running? Replicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0 Last_Error: Skip_Counter: 0 Exec_Master_Log_Pos: 254 Relay_Log_Space: 566 Until_Condition: None Until_Log_File: Until_Log_Pos: 0 Master_SSL_Allowed: No Master_SSL_CA_File: Master_SSL_CA_Path: Master_SSL_Cert: Master_SSL_Cipher: Master_SSL_Key: Seconds_Behind_Master: Master_SSL_Verify_Server_Cert: 0 No How Far Is Slave Behind? Last_IO_Errno: 0 Last_IO_Error: Last_SQL_Errno: 0 www.percona.com 30 Last_SQL_Error:
  • 31. MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 31
  • 32. Commands SQL Commands Adminstrative Commands Diagnostics Commands Shell Commands mysqlbinlog www.percona.com 32
  • 33. Administrative Commands Rotate binary log: FLUSH BINARY LOGS Rotate relay log: FLUSH RELAY LOGS START/STOP SLAVE IO_THREAD/SQL_THREAD Remove binary logs: PURGE MASTER LOGS TO ‘mysql-bin.000005’; PURGE MASTER LOGS BEFORE ‘2012-01-01 00:00:00’; Remove all binary logs: RESET MASTER Remove slave configuration and files: RESET SLAVE www.percona.com 33
  • 34. Diagnostics Commands On Master SHOW MASTER STATUS SHOW PROCESSLIST SHOW SLAVE HOSTS SHOW BINLOG EVENTS On Slave SHOW SLAVE STATUS SHOW PROCESSLIST www.percona.com 34
  • 35. On Master:SHOW MASTER STATUS Current binary log file and position: master> SHOW MASTER STATUSG *************************** 1. row *************************** File: mysql-bin.000008 Position: 254 Binlog_Do_DB: Binlog_Ignore_DB: 1 row in set (0.00 sec) www.percona.com 35
  • 36. On Master: SHOW PROCESSLIST Find Connected Slaves using SHOW PROCESSLIST: master> SHOW PROCESSLISTG ... *************************** 2. row *************************** Id: 4 User: repl Host: localhost:43537 db: NULL Command: Binlog Dump Time: 1264 State: Has sent all binlog to slave; waiting for binlog to be updated Info: NULL ... www.percona.com 36
  • 37. On Master: SHOW SLAVE HOSTS Shows connected slaves with their server-id: master> SHOW SLAVE HOSTS; +-----------+-----------+------+-----------+ | Server_id | Host | Port | Master_id | +-----------+-----------+------+-----------+ | 2 | slave | 3306 | 1 | +-----------+-----------+------+-----------+ 1 row in set (0.00 sec) Only works when slaves have configured: report-host, report-user, report-password, report-port www.percona.com 37
  • 38. On Slave: SHOW PROCESSLIST Slave Thread Status: SLAVE> SHOW PROCESSLISTG *************************** 1. row *************************** Id: 5 User: system user Host: db: NULL Command: Connect Time: 88611 State: Waiting for master to send event Info: NULL *************************** 2. row *************************** Id: 8 User: system user Host: db: NULL Command: Connect Time: 83 State: Has read all relay log; waiting for the slave I/O thread to update it Info: NULL www.percona.com 38
  • 39. MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 39
  • 40. Other Common Configuration Options Filtering: binlog-%, replicate-% Don’t start replication at start: skip_slave_start Put relay log events in it’s own binary log: log_slave_updates Disallow writing on slaves: read_only Automatically remove binlogs: expire_logs_days Change binlog format: binlog_format www.percona.com 40
  • 41. Filtering on Master binlog-do-db=..., binlog-ignore-db=... Warning! Different behavior between SBR and RBR: SBR: Log all statements executed if the ‘default database’ (use database) should be binlogged RBR: Log all row changes of the databases that should be binlogged www.percona.com 41
  • 42. Filtering on Slave replicate-do-db= & replicate-ignore-db= Warning! Different behavior between SBR and RBR Similar to binlog-do/ignore-db replicate-do/ignore-table: Filter on table level replicate-wild-do/ignore-table: Use wildcards (%,_) to filter on table level replicate-rewrite-db=db1->db2 www.percona.com 42
  • 43. MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 43
  • 44. Replication Architectures Master-Slave Master-Master Multi Tiered Replication Circular Replication www.percona.com 44
  • 45. Master-Slave Master Slave www.percona.com 45
  • 46. Master-Slave Application Master Slave www.percona.com 45
  • 47. Master-Slave Application Master Slave www.percona.com 45
  • 48. Master-Slave Application Writes/Reads Master Slave www.percona.com 45
  • 49. Master-Slave Application Writes/Reads Master Slave www.percona.com 45
  • 50. Master-Slave Application Writes/Reads Master Reads Slave www.percona.com 45
  • 51. Master-Slave Master Slave Slave Slave www.percona.com 46
  • 52. Master-Slave Application Master Slave Slave Slave www.percona.com 46
  • 53. Master-Slave Application Master Slave Slave Slave www.percona.com 46
  • 54. Master-Slave Application Writes/Reads Master Slave Slave Slave www.percona.com 46
  • 55. Master-Slave Application Writes/Reads Master Slave Slave Slave www.percona.com 46
  • 56. Master-Slave Application Writes/Reads Master Reads Slave Slave Slave www.percona.com 46
  • 57. Master-Slave Application Writes/Reads Master Reads Slave Slave Slave www.percona.com 46
  • 58. Master-Slave Application Writes/Reads Master Reads Slave Slave Slave www.percona.com 46
  • 59. Master-Slave Scaling Reads: Slaves can take reads (remember asynchronous!) Reporting/Search queries can go to separate slave Does not take resources on master ‘live-site’-slave. (‘live site’: lower response time requirements than reports) Can have other indexes, even other tables (summary tables,...) Not much benefit when too much writes Maintenance (schema changes...) Upgrade slaves first: Take slave offline SET SQL_LOG_BIN=0; <-don’t put this session queries in ALTER TABLE ...; the binary log SET SQL_LOG_BIN=1; www.percona.com 47
  • 60. Master-Slave: Reporting Queries Master Slave Slave Slave www.percona.com 48
  • 61. Master-Slave: Reporting Queries Application Master Slave Slave Slave www.percona.com 48
  • 62. Master-Slave: Reporting Queries Application Master Slave Slave Slave www.percona.com 48
  • 63. Master-Slave: Reporting Queries Application Writes/Reads Master Slave Slave Slave www.percona.com 48
  • 64. Master-Slave: Reporting Queries Application Writes/Reads Master Reads Slave Slave Slave www.percona.com 48
  • 65. Master-Slave: Reporting Queries Application Writes/Reads Master Reads Slave Slave Slave www.percona.com 48
  • 66. Master-Slave: Reporting Queries Application Writes/Reads Master Reads Slave Slave Slave www.percona.com 48
  • 67. Master-Slave: Reporting Queries Application Writes/Reads Reporting Master Reads Slave Slave Slave www.percona.com 48
  • 68. Master-Slave: Reporting Queries Application Writes/Reads Reporting Master Reads Slave Slave Slave www.percona.com 48
  • 69. Master-Slave: Write Intensive Master Slaves Master Slaves Capacity left for READS Capacity left for READS Capacity taken by WRITES Capacity taken by WRITES www.percona.com 49
  • 70. Master-Master Master Master www.percona.com 50
  • 71. Master-Master Used for: High Availability Maintenance Tasks Write to 1 master, failover to the passive master when necessary Passive master is a real slave, can be used for reads Scale Writes? NO! Every write still has to be performed on both masters Writing to both masters at the same time? NO*! Can cause inconsistencies even with auto_increment_increment/ auto_increment_offset problems can happen www.percona.com 51
  • 72. Master-Master: Reads & Writes Application Writes/Reads Reads Master Master www.percona.com 52
  • 73. Master-Master: Maintenance Application Writes/Reads Master Master www.percona.com 53
  • 74. Master-Master: Maintenance Application Writes/Reads Master Master SET SQL_LOG_BIN=0; ALTER TABLE ...; ... SET SQL_LOG_BIN=1; www.percona.com 53
  • 75. Master-Master: Maintenance Application Writes/Reads Master Master www.percona.com 53
  • 76. Master-Master: Maintenance Application Writes/Reads Master Master SET SQL_LOG_BIN=0; ALTER TABLE ...; ... SET SQL_LOG_BIN=1; www.percona.com 53
  • 77. Master-Master: Write to Both? Inconsistencies Application Master Master +--------+----------------+ +--------+----------------+ | userid | email | | userid | email | +--------+----------------+ +--------+----------------+ | 1 | [email protected] | | 1 | [email protected] | +--------+----------------+ +--------+----------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), UNIQUE KEY idx_email (email) ); www.percona.com 54
  • 78. Master-Master: Write to Both? Inconsistencies Application UPDATE users SET email=‘[email protected]’ UPDATE users SET where userid=1; email=‘[email protected]’ where userid=1; Master Master +--------+----------------+ +--------+----------------+ | userid | email | | userid | email | +--------+----------------+ +--------+----------------+ | 1 | [email protected] | | 1 | [email protected] | +--------+----------------+ +--------+----------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), UNIQUE KEY idx_email (email) ); www.percona.com 54
  • 79. Master-Master: Write to Both? Inconsistencies Application UPDATE users SET email=‘[email protected]’ UPDATE users SET where userid=1; email=‘[email protected]’ where userid=1; Master Master +--------+------------------+ +--------+-------------------+ | userid | email | | userid | email | +--------+------------------+ +--------+-------------------+ | 1 | [email protected] | | 1 | [email protected] | +--------+------------------+ +--------+-------------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), UNIQUE KEY idx_email (email) ); www.percona.com 54
  • 80. Master-Master: Write to Both? Inconsistencies Application UPDATE users SET email=‘[email protected]’ where userid=1; Master Master UPDATE users SET email=‘[email protected]’ where userid=1; +--------+------------------+ +--------+-------------------+ | userid | email | | userid | email | +--------+------------------+ +--------+-------------------+ | 1 | [email protected] | | 1 | [email protected] | +--------+------------------+ +--------+-------------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), UNIQUE KEY idx_email (email) ); www.percona.com 54
  • 81. Master-Master: Write to Both? Inconsistencies Application UPDATE users SET email=‘[email protected]’ where userid=1; Master Master UPDATE users SET email=‘[email protected]’ where userid=1; +--------+-------------------+ +--------+------------------+ | userid | email | | userid | email | +--------+-------------------+ +--------+------------------+ | 1 | [email protected] | | 1 | [email protected] | +--------+-------------------+ +--------+------------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), UNIQUE KEY idx_email (email) ); www.percona.com 54
  • 82. Master-Master: Write to Both? Replication Breaks Application Master Master +--------+----------------+ +--------+----------------+ | userid | email | | userid | email | +--------+----------------+ +--------+----------------+ | 1 | [email protected] | | 1 | [email protected] | +--------+----------------+ +--------+----------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), UNIQUE KEY idx_email (email) ); www.percona.com 55
  • 83. Master-Master: Write to Both? Replication Breaks Application UPDATE USERS SET email=‘[email protected]’ INSERT INTO USERS WHERE userid=1; (email) VALUES (‘[email protected]’) Master Master +--------+----------------+ +--------+----------------+ | userid | email | | userid | email | +--------+----------------+ +--------+----------------+ | 1 | [email protected] | | 1 | [email protected] | +--------+----------------+ +--------+----------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), UNIQUE KEY idx_email (email) ); www.percona.com 55
  • 84. Master-Master: Write to Both? Replication Breaks Application UPDATE USERS SET email=‘[email protected]’ INSERT INTO USERS WHERE userid=1; (email) VALUES (‘[email protected]’) Master Master +--------+--------------------+ +--------+--------------------+ | userid | email | | userid | email | +--------+--------------------+ +--------+--------------------+ | 1 | [email protected] | | 1 | [email protected] | | 2 | [email protected] | +--------+--------------------+ +--------+--------------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), UNIQUE KEY idx_email (email) ); www.percona.com 55
  • 85. Master-Master: Write to Both? Replication Breaks Application UPDATE USERS SET email=‘[email protected]’ WHERE userid=1; Master Master INSERT INTO USERS (email) VALUES (‘[email protected]’) +--------+--------------------+ +--------+--------------------+ | userid | email | | userid | email | +--------+--------------------+ +--------+--------------------+ | 1 | [email protected] | | 1 | [email protected] | | 2 | [email protected] | +--------+--------------------+ +--------+--------------------+ CREATE TABLE users ( userid INT AUTO_INCREMENT, Error 'Duplicate entry '[email protected]' email VARCHAR(128) NOT NULL, PRIMARY KEY (userid), for key 'idx_email'' on query. Default UNIQUE KEY idx_email (email) database: 'test'. Query: 'insert into ); users(email) values ('[email protected]')' www.percona.com 55
  • 86. Multi Tiered Replication Master Slave Slave Slave Slave Slave www.percona.com 56
  • 87. Multi Tiered Replication 2 Second query takes 6 seconds to reach the 3rd level Top level slaves could be a master for some dbs/tables too Replication main data (users...) to top level slaves Top level slaves are sort of functionally partitioned www.percona.com 57
  • 88. Multi Tiered Replication: Delay Master Slave Slave Slave Slave Slave www.percona.com 58
  • 89. Multi Tiered Replication: Delay Master 2 Seconds Slave Slave Slave Slave Slave www.percona.com 58
  • 90. Multi Tiered Replication: Delay Master 2 Seconds 2 Seconds Slave Slave Slave Slave Slave www.percona.com 58
  • 91. Multi Tiered Replication: Delay Master 2 Seconds 2 Seconds Slave Slave Slave 2 Seconds Slave Slave www.percona.com 58
  • 92. Multi Tiered Replication: Top Level Slaves MASTER Master MASTER SEARCH LOG Slave Slave Slave SEARCH SEARCH Slave Slave www.percona.com 59
  • 93. Multi Tiered Replication Master Slave Slave Slave Slave Slave No Updates Anymore www.percona.com 60
  • 94. Circular Replication Master Master Master Master www.percona.com 61
  • 95. Circular Replication Master Master Master Master www.percona.com 62
  • 96. Circular Replication Master Master Master Master www.percona.com 63
  • 97. MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 64
  • 98. Common Issues Replication Lag Replication Breaking Crash Safe Replication Consistency www.percona.com 65
  • 99. Replication Lag - Causes Single threaded execution on slave!!! Long running queries with SBR: will take ~same time on slave Many row changes with RBR MyISAM & table level locking: Long running SELECT on slave might block replication Schema changes: 20min on master, 20min on slave <-- 20 min replication lag www.percona.com 66
  • 100. Replication Lag - Tips 1 Optimize DML Statements Avoid DDL Statements in Replication (SQL_LOG_BIN=0) Hardware specifications usually need to be equal or better on slave MySQL 5.6: http://d2-systems.blogspot.com/2011/04/mysql-56x-feature-preview-multi.html Ensure BBU&Write Back Cache is used or lower durability: innodb_flush_log_at_trx_commit=2 Change architecture: functional/horizontal partitioning www.percona.com 67
  • 101. Replication Lag - Tips 2 Try to avoid SQL Thread to need to do disk I/O: Replication Booster (Yoshinori Matsunobu) prefetches relay logs and converts queries to select and runs them, causing data to be cached before SQL thread reaches innodb_fake_changes http://www.percona.com/doc/percona-server/5.5/management/ innodb_fake_changes.html http://dom.as/2011/12/03/replication-prefetching/ www.percona.com 68
  • 103. Replication Breaking - Examples Last_Errno: 1146 Last_Error: Error 'Table 'db.table' doesn't exist' on query. Default database: 'userdb'. Query: '...' Last_Errno: 1062 Last_Error: Error 'Duplicate entry '1748099' for key 1' on query. Default database: 'db'. Query: 'INSERT INTO table (url) VALUES(‘http://www.google.com')' Last_Errno: 1053 Last_Error: Query partially completed on the master (error on master: 1053) and was aborted. There is a chance that your master is inconsistent at this point. If you are sure that your master is ok, run this query manually on the slave and then restart the slave with SET GLOBAL SQL_SLAVE_SKIP_COUNTER=1; START SLAVE; . Query: ALTER TABLE ‘users’ ADD ‘name’ VARCHAR(128) NULL DEFAULT; www.percona.com 70
  • 104. Replication Breaking - Causes Writes happening on Slaves SBR with bad statements Crashes: Relay Log Corruption Different schemas Temporary tables Mixing MyISAM with InnoDB Different behavior between MySQL versions (minor/major) Killing queries that change MyISAM tables will be partially executed, and break replication ... www.percona.com 71
  • 105. Replication Breaking - Fixing Questions to ask yourself: Why? Where? Impact? Quick ‘fix’: SET GLOBAL SQL_SLAVE_SKIP_COUNTER=1; START SLAVE; Causes 1 event to be skipped Causes inconsistencies!!! Look at: Check error & Investigate data on master/slave MySQL errorlogs SHOW SLAVE STATUSG mysqlbinlog on relaylogs/binarylogs and investigate pt-slave-restart More On: http://www.percona.com/files/presentations/percona-live/london-2011/ PLUK2011-diagnosing-and-fixing-mysql-replication.pdf www.percona.com 72
  • 106. Crash Safe Replication On master: sync_binlog=1 to fsync at every binlog write Performance impact, mainly on: Ext3 filesystem http://www.mysqlperformanceblog.com/2009/01/21/beware-ext3-and-sync-binlog-do-not-play-well-together/ High write-response time disksubsystem (no WriteBackCache& BBU) On slave: relay-log.info/master.info: not durable/consistent! When OS crash, old information might be in the file If InnoDB only: use innodb_overwrite_relay_log_info in Percona Server: http://www.percona.com/doc/percona-server/5.5/reliability/ innodb_recovery_update_relay_log.html www.percona.com 73
  • 107. Consistency Replication can cause inconsistencies: Statement Based Replication Certain functions like UUID()... UPDATE/DELETE with LIMIT without ORDER BY unique key Writing to multiple masters Writing to slaves (by accident? use read_only) Failover done wrong MyISAM with killing queries and/ord MySQL Crashes Wrongly restored slaves Replication broke and used SQL_SLAVE_SKIP_COUNTER ... How to know if my data is consistent? www.percona.com 74
  • 108. Consistency Checking Consistency: pt-table-checksum Checksums chunks of data on master and slaves Monitors replication lag Low checksum response time to lower impact on production Uses Replication to ensure consistent view of data Fixing Consistency: pt-table-sync Can checksum and use pt-table-checksum results Fixes inconsistencies www.percona.com 75
  • 109. MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 76
  • 110. Replication Use Cases Scale Reads High Availability Backups www.percona.com 77
  • 111. High Availability Failover: Virtual IPs Change IP in application servers Warning: Split-Brain possible!!! Ensure no writes happen on old master before moving Make sure new master is in sync Scripts available to automate failover: MySQL-MHA http://code.google.com/p/mysql-master-ha/ MMM (not-recommended) http://mysql-mmm.org/ Percona-PRM http://www.mysqlperformanceblog.com/2011/11/29/percona-replication-manager-a- solution-for-mysql-high-availability-with-replication-using-pacemaker/ www.percona.com 78
  • 112. High Availability Due to asynchronous’ness, data might be lost: Semi-Synchronous Replication: ensure at least one slave’s IO thread has received the event before the transaction is committed. http://dev.mysql.com/doc/refman/5.5/en/replication-semisync.html www.percona.com 79
  • 113. Backups Point In Time Recovery, using binary logs Delayed slave Backup Slaves www.percona.com 80
  • 114. Incremental / Point In Time Recovery Restore Full Backup from your favorite backup tool Replay binary logs with mysqldump from the last position of the backup # mysqlbinlog --start-position=15115 1sbinarylog | mysql # mysqlbinlog next-binary-logs | mysql If PITR, stop at the desired position/time: # mysqlbinlog --stop-position=102151 binarylog | mysql # mysqlbinlog --stop-datetime=“2012-01-01 23:00:00” lastbinarylog | mysql www.percona.com 81
  • 115. Delayed Slave Deliberately lag a slave for a predefined amount of time Decrease recovery time in case of bad changes caused by: Humans (DROP DATABASE) Application (DELETE FROM table;) How to configure: pt-slave-delay --delay 60m (http://www.percona.com/doc/percona-toolkit/2.0/pt-slave-delay.html) 5.6 Built-in feature: > CHANGE MASTER TO MASTER_DELAY=3600; When a problem happens stop replication just before the malicious statement. START SLAVE UNTIL MASTER_LOG_FILE='log_name', MASTER_LOG_POS = pos; www.percona.com 82
  • 116. Backup using Slaves Online Backups might not be possible on active master: Too much impact to make online: InnoDB backup (using MySQL enterprise backup or XtraBackup) LVM Snapshots MyISAM tables Offsite Backup www.percona.com 83
  • 117. MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 84
  • 118. Other Replication Implementations Tungsten Replicator Uses binary log Parallel replication Enhanced filtering Multi-master Replication between different databases Galera Cluster Does not use binary log Synchronous replication Active-active master Parallel replication Percona XtraDB Cluster! http://www.mysqlperformanceblog.com/2012/01/09/ announcement-of-percona-xtradb-cluster-alpha-release/ www.percona.com 85
  • 121. MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 88
  • 122. Tools & More Info Percona Toolkit http://www.percona.com/software/percona-toolkit/ pt-slave-find, pt-table-checksum, pt-table-sync, pt-slave-delay, pt-slave-restart, pt-heartbeat Percona Server http://www.percona.com/software/percona-server/ OpenArk kit http://code.openark.org/forge/openark-kit Replication Booster https://github.com/yoshinorim/replication-booster-for-mysql High Availability MMM http://mysql-mmm.org/ Percona-PRM http://www.mysqlperformanceblog.com/2011/11/29/percona-replication-manager-a- solution-for-mysql-high-availability-with-replication-using-pacemaker/ MySQL-MHA http://code.google.com/p/mysql-master-ha/ High Performance MySQL, 2nd Edition: http://shop.oreilly.com/product/9780596101718.do www.percona.com 89
  • 123. MySQL Replication Replication Overview Binary Logs Setting Up Replication Commands Other Common Configuration Settings Replication Architectures Common Issues Replication Use Cases Other Replication Implementations Tools www.percona.com 90
  • 124. Kenny Gryp <[email protected]> @gryp We're Hiring! www.percona.com/about-us/careers/