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Diffstat (limited to 'docs/databases.txt')
| -rw-r--r-- | docs/databases.txt | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/docs/databases.txt b/docs/databases.txt index 331313b..7f8468e 100644 --- a/docs/databases.txt +++ b/docs/databases.txt @@ -8,7 +8,7 @@ Gluster/Block MyISAM (no logs) 5 MB/s slow, but OK 200% ~ 50% No problems on reboot, but requires manual work if node crashes to detach volume. Galera INNODB 3.5 MB/s fast 3 x 200% - Should be perfect, but I am not sure about automatic recovery... Galera/Hostnet INNODB 4.6 MB/s fast 3 x 200% - - MySQL Slaves INNODB 5-8 MB/s fast 2 x 250% - Available data is HA, but caching is not. We can easily turn the slave to master. + MySQL Slaves INNODB 5-6 MB/s fast 2 x 250% - Available data is HA, but caching is not. We can easily turn the slave to master. DRBD MyISAM (no logs) 4-6 exp. ? I expect it as an faster option, but does not fit the OpenShift concept that well. @@ -150,5 +150,15 @@ Master/Slave replication slave side. Network is not a problem, it is able to get logs from the master, but it is significantly slower in applying it. The main performance killer is disk sync operations triggered by 'sync_binlog', INNODB log flashing, etc. Disabling it allows to bring performance on reasonable level. Still, - the master is caching at about 6-8 MB/s and slave at 4-5 MB/s only. + the master is caching at about 6-8 MB/s and slave at 4-5 MB/s only (sometimes drops bellow 2 MB/s). + + - The trouble I think is that Slave performs a lot of disk writes 'mysql-relay-bin.*', 'mysql-bin.*'. + If compared all together we get ~ 18 MB/s. The solution is to disable binary logging on the slave + side. We need 'relay' log to perform replication, but binary-log on the client will only be needed + if another slave would chain replicate for it. However, it is better to disable just logging of + data replicated from master by disabling 'log_slave_updates'. Then, if the slave is converted to master + it will automatically start logging. + + +
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