I have been using mysql master:master replication and was always able to check the status of replication using this command:
mysql > show slave status\G I was able to see this in the show slave status command:
Slave_IO_Running: Yes Slave_SQL_Running: Yes Seconds_Behind_Master: 0 The seconds_behind_master always let me know if I was behind on one of my servers.

I am not using galera and am not sure how to verify if everything is up to date. I have come across this article "Monitoring Cluster Status"
I realize I can use this command to see how many nodes are in the cluster:
SHOW GLOBAL STATUS LIKE 'wsrep_cluster_size';

But I am not sure if this command if good enough to tell whether or not they are exactly up to date:
SHOW GLOBAL STATUS LIKE 'wsrep_local_state_comment'; This command currently show synced but I cannot tell if this is the best way to tell if I am good to go.


If wsrep_local_state_comment, wsrep_ready, and wsrep_connected show the correct values, then that particular node is good.

There's no Seconds_Behind_Master equivalent, because Galera is synchronous -- a healthy node can't be lagging, by definition and by design... a slow node slows down all the others, it doesn't lag behind them.

  • 1
    For the wsrep_local_state_comment What would be a correct value? I am currently seeing it set to synced. – Som3guy Mar 20 '16 at 4:48
  • add wsrep_cluster_size which should be equal to the number of nodes of the cluster – jerichorivera Mar 20 '16 at 7:13
  • @Som3guy yes, 'Synced' is correct. – Michael - sqlbot Mar 20 '16 at 12:17
  • @jerichorivera it should equal the number of nodes, but if it isn't, that does not necessarily mean this node has a problem. With 3 nodes, if "node x" suddenly returns a value of "2" here, then "node x" would actually be one of the good nodes... So, while useful information, it doesn't really give you any new information about this node. – Michael - sqlbot Mar 20 '16 at 12:23
  • @Michael-sqlbot you are right – jerichorivera Mar 20 '16 at 12:27

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