[pve-devel] Default cache mode for VM hard drives

Alexandre DERUMIER aderumier at odiso.com
Mon Apr 13 11:16:50 CEST 2015


Hi,

Another difference is that cache=none|directsync is that vm use aio=native instead aio=threads.


(you can try cache=none,aio=threads in you disk config to change the behaviour).

Maybe it doesn't work well with drbd.


----- Mail original -----
De: "Stanislav German-Evtushenko" <ginermail at gmail.com>
À: "dietmar" <dietmar at proxmox.com>
Cc: "pve-devel" <pve-devel at pve.proxmox.com>, "aderumier" <aderumier at odiso.com>
Envoyé: Lundi 13 Avril 2015 10:23:19
Objet: Re: [pve-devel] Default cache mode for VM hard drives

Hello, 

I have an update on this issue. 

I have found circumstances when we get out of sync with directsync mode and made more test. What I found out so far was that out of sync only appear for cache modes with O_DIRECT, i.e. for those cache modes when host cache is bypassed. Write-back and write-through modes do not produce out of sync blocks with DRBD while "none" and "directsync" do. 

Best regards, 
Stanislav 



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