[pve-devel] backup ceph high iops and slow

[Alexandre DERUMIER]

>>We read 64K blocks, so 

Don't for for backup, but drive-mirror have a "granulary" option to change the block size:

 # @granularity: #optional granularity of the dirty bitmap, default is 64K.
 #               Must be a power of 2 between 512 and 64M.


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

De: "Dietmar Maurer" <dietmar at proxmox.com> 
À: "VELARTIS Philipp Dürhammer" <p.duerhammer at velartis.at>, "Dmitry Petuhov" <mityapetuhov at gmail.com>, "Alexandre DERUMIER" <aderumier at odiso.com> 
Cc: pve-devel at pve.proxmox.com 
Envoyé: Vendredi 17 Octobre 2014 13:02:29 
Objet: RE: [pve-devel] backup ceph high iops and slow 

> I agree. The main problem is with used space. 
> I didnt check for mirroring - but reading unused space for backup is super fast 
> (around 1200mb/sec) But used space only 40-50mb/sec and too many iops... 

We read 64K blocks, so 

40000/64 ==> 625 IOPS 

Maybe the pending ceph read-ahead changes solves that problem?