[pve-devel] lvm snapshots performance ?

[Alexandre DERUMIER]

Hi Dietmar,

I'm looking to maybe use lvm for my vms. (on top of shared sas jbod enclosures).

I'll like to use snapshots, but I see a lot of messages on internet about performance problem (big big slowdown)

http://www.nikhef.nl/~dennisvd/lvmcrap.html
http://johnleach.co.uk/words/613/lvm-snapshot-performance
http://www.mysqlperformanceblog.com/2009/02/05/disaster-lvm-performance-in-snapshot-mode/

Did you have tested it ? if yes,did you see  big slowdowns ?

I'll use ssd drive in my array, so maybe it'll help...



some user say that  dm-thin  can help 

https://github.com/jthornber/linux-2.6/blob/thin-stable/Documentation/device-mapper/thin-provisioning.txt

Do you know if dm-thin support is already added in lvm ? or something else which help snapshot performance?