mysql backups (was Re: Remote backups, reading from and writing to the same file)

Greg 'groggy' Lehey grog at
Sun Jan 15 15:12:43 PST 2006

On Sunday, 15 January 2006 at  4:28:15 +0100, Hans Nieser wrote:
> N.J. Thomas wrote:
>> * Hans Nieser <h.nieser at> [2006-01-13 00:25:14 +0100]:
>>> Among the things being backed up are my mysql database tables. This
>>> made me wonder wether the backup could possibly get borked when mysql
>>> writes to any of the mysql tables while tar is reading from them.
>> Yes. While MySQL is writing to the the database, it will put the files
>> on the disk in an inconsistent state. If you happen to copy those files
>> while they are in that state, MySQL will see a corrupted database.
> Thanks for the replies all. I think for the short term I will simply
> lock/shutdown my MySQL server (it is a home-server after all), in the long
> term I think I will look into snapshotting. I've also been thinking about
> just doing an SQL dump with mysqldump right before the backup, that will
> still copy along the tables which may be in an inconsistent state, but
> also the sql dump.

We (MySQL) are currently working on an online backup solution which
will address the issues you mention.  We don't have a firm date yet,
but it should be this year.  If you or anybody else has feature
requests, please let me know (preferably grog at, but this
address will work too).

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