>>Any other ideas how to reduce ceph-osd while doing randwrite? 
>>
>>Randread gives me with 3 VMs: 60.000 iops 
>>Randwrite gives me with 3 VMs: 25.000 iops 

Great to see that read scale !

For randwrite, what is the bottleneck now with filestore xattr use omap = true ?

Always cpu ?




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

De: "Stefan Priebe" <[email protected]> 
À: "Sage Weil" <[email protected]> 
Cc: [email protected] 
Envoyé: Jeudi 15 Novembre 2012 21:26:06 
Objet: Re: ceph-osd cpu usage 

Am 15.11.2012 16:14, schrieb Sage Weil: 
> On Thu, 15 Nov 2012, Stefan Priebe - Profihost AG wrote: 
> Hmm, most significant time seems to be in the allocator and doing 
> fsetxattr(2) (10%!). Also some path traversal stuff. 
Yes fsetxattr seems to be CPU hungry. 

> Can you try the wip-fd-simple-cache branch, which tries to spend less time 
> closing and reopening files? I'm curious how much of a different it will 
> make for you for both IOPS and CPU utilization. 
It seems to give me around 1000 iops across 3 VMs. 

> It is also possible to use leveldb for most attrs. If you set 
> 'filestore xattr use omap = true' it should put most attrs in leveldb. 
Tried this but this raises CPU by 20%. 

Any other ideas how to reduce ceph-osd while doing randwrite? 

Randread gives me with 3 VMs: 60.000 iops 
Randwrite gives me with 3 VMs: 25.000 iops 

Stefan 
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