Comments on: Pop quiz: when will a filesystem copy be an incomplete backup?

By: William

William — Mon, 04 Oct 2010 23:06:59 +0000

Federated tables, if anyone uses those, will obviously not be backed up.

Also, if you’ve changed important global settings, without updating my.cnf on disk. You may run into some performance issues ( in addition to cold cache’s).

By: Golan Zakai

Golan Zakai — Thu, 30 Sep 2010 11:22:51 +0000

In your case you just have to make sure you tar / untar it with preserve permissions of the actual files in used. when I want to restore backup I completely remove data directory and then open the tar which replace the old data directory.

If you use “FLUSH TABLES WITH READ LOCK” then LVM snapshot without slave stop or mysql shutdown then when you restore the data innodb will have to recover because the state of the snapshot was “hot” and it will take your time when you restore large data sets.

By: Alex

Alex — Mon, 27 Sep 2010 13:19:36 +0000

That seems to be a tricky question. If the question just about data then you should get all data. Unless it is not under the data directory, i.e. memory or federated tables, symlinks, tables not marked for replication etc.

However there is another question whether it will be possible to restore that data easily due to different MySQL versions\engines, users\permissions, OS settings etc.

By: sbester

sbester — Mon, 27 Sep 2010 10:03:20 +0000

you restore the datadir on some different filesystem/OS that doesn’t handle case sensitivity the same. this will instantly break all partitioned innodb tables for example.

By: Daniël van Eeden

Daniël van Eeden — Mon, 27 Sep 2010 08:18:35 +0000

If you only safe the datadir then the InnoDB log files might be elsewhere. The my.cnf is probably not in the datadir so the settings for the log files (size/location) could be different which could lose some transactions if InnoDB was not shutdown properly.