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matt.bennett
January 16th, 2009, 06:56 AM
Hi,

We are working towards a master-master MySQL setup for HA, with all reads and writes going to the currently selected (hot) master. In ordinary operation, we plan to use ZRM to make backups from the non-selected (cold) master.

In the event of the hot master failing, the cold master will become the destination for application reads and writes, as well as the database from which ZRM is making backups. In this situation, is ZRM capable of making hot backups - i.e. without locking the application out of the tables while the backup takes place?

Many thanks,
Matt.

zmanda_jacob
January 16th, 2009, 09:53 AM
The ZRM is capable of perform hot backups of InnoDB tables if used in conjunction with the InnoDB Hot Backup tool. By itself, the ZRM is able to perform "almost hot" backups using filesystem snapshots such as the LVM snapshot. In this case, the ZRM will execute a filesystem snapshot while a brief(around 1 second) read lock is placed on the database.

matt.bennett
January 17th, 2009, 03:11 AM
Thanks for your reply Jacob,

InnoDB hot-backup tool is propriatory is it not?

Filesystem snapshots via LVM seems like a reasonable solution for us. Is the length of the read-lock independent of the size of the database? If not, are there some approximate figures on how long it takes for databases of various sizes?

Finally, are there some examples/configs for zmanda performing backups and recoveries in this configuration?

Many thanks,
Matt.

zmanda_jacob
January 19th, 2009, 07:48 AM
The amount of time the snapshot will take will depend on the level of activity of the database or the filesystem on that spindle.

paddy
January 23rd, 2009, 05:25 PM
Thanks for your reply Jacob,

Finally, are there some examples/configs for zmanda performing backups and recoveries in this configuration?

Many thanks,
Matt.

Please take a look at http://www.zmanda.com/blogs/?p=47