Re: Testing Sandforce SSD

From: Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>
To: Greg Smith <greg(at)2ndquadrant(dot)com>
Cc: Josh Berkus <josh(at)agliodbs(dot)com>, pgsql-performance(at)postgresql(dot)org
Subject: Re: Testing Sandforce SSD
Date: 2010-08-03 00:12:41
Message-ID: AANLkTikQ=CUSoRy+MxYA2TAfk2hdipA4Uz_qYXyu+yhR@mail.gmail.com
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On Mon, Aug 2, 2010 at 6:07 PM, Greg Smith <greg(at)2ndquadrant(dot)com> wrote:
> Josh Berkus wrote:
>>
>> That doesn't make much sense unless there's some special advantage to a
>> 4K blocksize with the hardware itself.
>
> Given that pgbench is always doing tiny updates to blocks, I wouldn't be
> surprised if switching to smaller blocks helps it in a lot of situations if
> one went looking for them.  Also, as you point out, pgbench runtime varies
> around wildly enough that 10% would need more investigation to really prove
> that means something.  But I think Yeb has done plenty of investigation into
> the most interesting part here, the durability claims.

Running the tests for longer helps a lot on reducing the noisy
results. Also letting them runs longer means that the background
writer and autovacuum start getting involved, so the test becomes
somewhat more realistic.

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