From: Yeb Havinga <yebhavinga@gmail.com>
To: Matthew Wakeling <matthew@flymine.org>
Cc: Greg Smith <greg@2ndquadrant.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Testing Sandforce SSD
Date: Mon, 26 Jul 2010 12:29:42 +0200
Message-ID: <4C4D6396.5020707@gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1007261045470.20471@aragorn.flymine.org>
References: <4C4A9452.9070100@gmail.com>
<4C4B1F84.5030306@2ndquadrant.com>
<4C4C83DF.3010703@gmail.com>
<4C4C8CCC.7080406@gmail.com>
<alpine.DEB.2.00.1007261045470.20471@aragorn.flymine.org>
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
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To: pgsql-performance@postgresql.org
Cc: yebhavinga@gmail.com, matthew@flymine.org, greg@2ndquadrant.com
Subject: Re: Testing Sandforce SSD
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