Ending up on this page means that you already know that whisper is not that disk space efficient. Unless you have unlimited disk space, which you don’t have, at some point you would want to clean it up. This is how I am doing it: 1. Delete old metrics of ours that haven’t been written to … Continue reading Clean up whisper database
This one in not very different than Topology refactoring using classic MySQL replication commands – version 1, actually it’s the other way around. Context: Initial state: dbfoo1(M) – dbfoo2(S) \ dbfoo3(S) Desired state: dbfoo1(M) – dbfoo2(MS) – dbrfoo3(S) Let’s get it done: stop slave on dbfoo3 MariaDB [(none)]> stop slave; check the “freezing point” on … Continue reading Topology refactoring using classic MySQL replication commands – version 2
A week ago I wrote a post about promoting a mysql slave as master. Today I will write topology refactoring using classic replication commands. Context: Initial state: dbfoo1(M) – dbfoo2(MS) – dbrfoo3(S) Desired state: dbfoo1(M) – dbfoo2(S) \ dbfoo3(S) Let’s get to work: stop slave on dbfoo3 MariaDB [(none)]> stop slave; check the “freezing point” … Continue reading Topology refactoring using classic MySQL replication commands – version 1
I assume you you have a high availability (master – slave topology) setup. I will be brief and technical on this one :) Context: dbfoo1 is master and dbfoo2 is slave – dbfoo1(M) – dbfoo2(S) dbfoo2 has to be promoted to master – dbfoo2(M) – dbfoo1(S) note that in some cases the slave requires a … Continue reading mysql: Promoting a slave to master
It happened today… why? Well, I was testing parallel replication (slave_parallel_threads) and after setting the number of threads to zero and when started the slave I got this wonderful error message: MariaDB [(none)]> show slave status\G *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: master.example.com Master_User: user Master_Port: 3306 Connect_Retry: 60 … Continue reading Relay log read failure: Could not parse relay log event entry
Why?! To avoid a lengthy warmup period after restarting the server, particularly for instances with large InnoDB buffer pools. Things to be added to /etc/mysq/my.cnf: # Shortened warm-up times with a preloaded InnoDB buffer pool innodb_buffer_pool_dump_at_shutdown=ON innodb_buffer_pool_load_at_startup=ON Basically when MySQL receives the TERM signal will dump the InnoDB buffer pool /data/db/mysql/ib_buffer_pool and it will load it … Continue reading mysql: preload InnoDB buffer pool
Source: http://www.mysqlperformanceblog.com/2008/02/04/finding-out-largest-tables-on-mysql-server/