Toolserver:Admin:Change the replication master
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Before you change the master, you need the new master position. It's usually in the server admin log, but if not, ask for it in #wikimedia-tech. If the master was changed by the WMF-guys because of a schema-change it is important to wait until the (then) old master was modified by the WMF-guys too.
If the master host changed[edit]
If the master is changing, you need to reconfigure SQL-Proxy to use the new master. Then choose one of the following options, based on the replication type.
For a MySQL-replicated cluster[edit]
- Stop the MySQL slave:
STOP SLAVE; - Change the MySQL master position:
CHANGE MASTER TO master_log_pos=..., master_log_file='...'; - Restart replication:
START SLAVE;
For a trainwreck-replicated cluster[edit]
- Stop the appropriate trainwreck instance:
svcs trainwreck; svcadm disable trainwreck:instance - Wait for the reader and writer threads to exit (
tail -f /var/svc/log/network-trainwreck:instance.log) - Delete the file
0.logpos, which will be in thestatedirdefined in/etc/trainwreck/instance.conf. - Run trainwreck manually:
/opt/local/bin/trainwreck -af /etc/trainwreck/instance.conf -F <logfile> -p <position> - Stop it:
/opt/local/bin/twctl -c /etc/trainwreck/instance.conf shutdown - Start it properly:
svcadm enable trainwreck:instance