[Cialug] VMs & Replication

[Matthew Steven]

On 03/18/2011 12:48 PM, Matthew Nuzum wrote:
>
> Matt, you take the snapshots outside of the VM? Doesn't that cause 
> potential for consistency problems?
>
Absolutely.

Even though LVM sync's everything to disk on the original volume before 
the snapshot COW starts, that doesn't necessarily guarantee consistency 
since the database will do with the data as it wilt.

Coordinating a flush tables/lock before the snapshot creation is a good 
way to handle that. Or if that's likely to be mis-timed or inconvenient 
in your deployment, you can also just ensure that the system dumps the 
tables to disk regularly. Or use the db's built in syncronization. The 
list goes on and on!

-- 

Matthew Steven
http://www.geniusweb.com/
(515) 999 0842