Re: requests are blocked - problem

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Hello,

On Thu, 20 Aug 2015 08:25:16 +0200 Jacek Jarosiewicz wrote:

> On 08/20/2015 03:07 AM, Christian Balzer wrote:
> > For a realistic comparison with your current setup, a total rebuild
> > would be in order. Provided your cluster is testing only at this point.
> >
> > Given your current HW, that means the same 2-3 HDDs per storage node
> > and 1 SSD as journal.
> >
> > What exact maker/model are your SSDs?
> >
> > Again, more HDDs means more (sustainable) IOPS, so unless your space
> > requirements (data and physical) are very demanding, double the amount
> > of 3TB HDDs would be noticeably better.
> >
> > Christian
> >
> 
> The cluster is a test setup, eventually we will have lots more hdds 
> (probably we will fill both chassises with drives - 44 drives each), 
> just starting with this number for testing purposes.
> 
> For the ssd's we use Intel DC S3710 (we ran into dsync problems with 
> intel 530 series drives before, so we switched to recommended ones).
> 
Ah yes. The S3710s are 200GB, I guess the 240GB came from the 530s. ^o^
Also for use as journals the older 3700 is actually better suited, as it
has a higher sequential write rate.
In everything else the 3710 is faster. 

> By "total rebuild" do You mean reinitializing the whole cluster 
> (monitors/osds) and starting from scratch?
> 
Well, not the the monitors, but starting from scratch might actually be
the fastest way. 
Unless you have another 10 HDDs and 4 SSDs (1 per storage node) for
journals lying around, to get a "fair" comparison to your current install.

Realistically you would of course compare something that is about the same
size and cost, so more like 16 HDDs.

Christian
-- 
Christian Balzer        Network/Systems Engineer                
chibi@xxxxxxx   	Global OnLine Japan/Fusion Communications
http://www.gol.com/
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