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Message-ID: <4C4D6396.5020707@gmail.com>
Date: Mon, 26 Jul 2010 12:29:42 +0200
From: Yeb Havinga <yebhavinga@gmail.com>
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To: Matthew Wakeling <matthew@flymine.org>
CC: Greg Smith <greg@2ndquadrant.com>, pgsql-performance@postgresql.org
Subject: Re: Testing Sandforce SSD
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	<alpine.DEB.2.00.1007261045470.20471@aragorn.flymine.org>
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Matthew Wakeling wrote:
> On Sun, 25 Jul 2010, Yeb Havinga wrote:
>> Graph of TPS at http://tinypic.com/r/b96aup/3 and latency at 
>> http://tinypic.com/r/x5e846/3
>
> Does your latency graph really have milliseconds as the y axis?
Yes
> If so, this device is really slow - some requests have a latency of 
> more than a second!
I try to just give the facts. Please remember that particular graphs are 
from a read/write pgbench run on a bigger than RAM database that ran for 
some time (so with checkpoints), on a *single* $435 50GB drive without 
BBU raid controller. Also, this is a picture with a few million points: 
the ones above 200ms are perhaps a hundred and hence make up a very 
small fraction.

So far I'm pretty impressed with this drive. Lets be fair to OCZ and the 
SandForce guys and do not shoot from the hip things like "really slow", 
without that being backed by a graphed pgbench run together with it's 
cost, so we can compare numbers with numbers.

regards,
Yeb Havinga