[pve-devel] lvm snapshots performance ?

[Alexandre DERUMIER]

I have found that rhel 6.3 support dm-thinp and lvm2 too.

https://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/6.3_Release_Notes/storage.html

So maybe it's already support in proxmox kernel ?

Do you know if it's work in cluster ?

----- Mail original -----

De: "Alexandre DERUMIER" <aderumier at odiso.com>
À: pve-devel at pve.proxmox.com
Envoyé: Jeudi 28 Juin 2012 08:10:14
Objet: lvm snapshots performance ?

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?


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Alexandre D e rumier

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