… seconds or even longer. There are multiple reasons why application falls behind and why we see those lag spikes: Slave Server Load – MySQL Replication… know how to measure replication lag – MySQL Toolkit has a great tool for real latency measurement. Do not trust Seconds_Behind_Master too much, even…
Post: Infinite Replication Loop
October 10, 2011 By 2 Comments
… two actual masters. Let’ s have a look first at the normal flow: Replication flow: [1] When you setup MySQL replication, you … replication loop ? When you have an infinite replication loop, the value of Seconds_behind_master will have many randomly looking values. The value of Seconds_behind_master…
Post: How to Monitor MySQL with Percona's Nagios Plugins
February 22, 2012 By 8 Comments
… needed. Replication is one thing that needs to be monitored in two dimensions, which shouldn’t be combined: delay (Seconds_behind_master or the delay indicated by the pt-heartbeat tool, if you choose), and actual failure. The pmp-check-mysql-replication-delay…
Post: Finding your MySQL High-Availability solution – Replication
November 13, 2009 By 6 Comments
…a second …MySQL replication. All writes are going to the master while reads are spread between the master and the slave. Upon failure of the master, replication…replication on one of the MySQL servers lags behind too much, its read VIP will be moved to another server. As a conclusion, replication…
Post: How SHOW SLAVE STATUS relates to CHANGE MASTER TO
July 7, 2008 By 21 Comments
… know MySQL Replication (statement based) works by fetching statements from MASTERs binary log and executing them on the SLAVE. Since MySQL 4….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: 0 …
Post: Benchmarking Galera replication overhead
October 13, 2011 By 12 Comments
… logs rotation And, second, much more serious problem: After 1800 sec of run, slave in regular MySQL replication was behind of master by 1000 sec. You can calculate how many transactions slave is missing. For Galera replication this is…
Post: Emulating global transaction ID with pt-heartbeat
November 4, 2011 By 6 Comments
…for a future version of MySQL. A global transaction ID lets you determine a server’s replication position reliably, among other benefits…replication should be running pt-heartbeat already to get a reliable indicator of actual replication delay. This avoids the many problems with Seconds_behind_master…
Post: Percona Replication Manager, a solution for MySQL high availability with replication using Pacemaker
November 29, 2011 By 94 Comments
…master fails, a new master is promoted from the slaves, no master to master setup needed. Selection of master…mysql_replication” \ replication_info=”10.2.2.162|mysql…MySQL on a slave that lags behind…
Post: Three ways to know when a MySQL slave is about to start lagging
October 8, 2008 By 8 Comments
…mysql> SELECT * FROM INFORMATION_SCHEMA.USER_STATISTICS WHERE USER=’#mysql_system#’\G *************************** 1. row *************************** USER: #mysql… (because there are two replication threads on the slave)…especially if you’re monitoring Seconds_behind_master instead of using mk-…
Post: Estimating Replication Capacity
July 20, 2010 By 4 Comments
…MySQL replication to become bottleneck when Master…replication capacity the ability to replicate the master load. If replication is able to replicate 3 times the write load from the master without falling behind…
