Re: [Users] backups
Blaster schreef op 27-11-2013 17:23:
On 11/27/2013 4:24 AM, Martijn Grendelman wrote:
> The problem with snapshot-based backups is, that they are usually only
> crash-consistent, meaning that they contain the state of a system's
> disks as they would be if you pulled the power plug on a server. If
> you restore a system from this type of backup, you would see file
> system recovery happening at the first boot, and you risk data loss
> from -for example- database servers.
The work-around for this is to SSH into the guest first, put the
database into backup mode(maybe run sync a time or two to flush out as
much from RAM as possible), take the snap shot, ssh back in to resume
the database, backup the snap, delete the snap.
Yes, for example for MySQL, you could
1. issue a FLUSH TABLES WITH READ LOCK statement
2. create a snapshot
3. issue a UNLOCK TABLES statement
before starting a backup from the snapshot, to get a consistent backup
of the binary table space.
Cheers,
Martijn.