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 many times to need a quick access to the remote console of a server like HP’s ILO and not be able to open a web browser just to access it. So let access it via SSH. Here goes. [codesyntax lang=”bash”] ssh ilo_admin@ip_address [/codesyntax] 2. Enter your ILO admin account and password. After that you will see … Continue reading Access HP’s ILO remote console via SSH →
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 →
Sometimes connecting to the collectd unixsocket is not possible giving a connection refused. This can be fixed manually by removing manually the socket file [codesyntax lang=”bash”] rm /var/run/collectd-unixsock [/codesyntax] and then restart collectd [codesyntax lang=”bash”] /etc/init.d/collectd restart [/codesyntax] collectd does not create a new socket file when there is already such a file. But the … Continue reading How to fix “ERROR: Connecting to daemon at /var/run/collectd-unixsock failed” →
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 →
I can't memorize much, so I take notes!