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Message-ID: <4C56DD8B.6050303@gmail.com>
Date: Mon, 02 Aug 2010 17:00:27 +0200
From: Yeb Havinga <yebhavinga@gmail.com>
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To: Merlin Moncure <mmoncure@gmail.com>
CC: pgsql-performance@postgresql.org, Greg Smith <greg@2ndquadrant.com>
Subject: Re: Testing Sandforce SSD
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Merlin Moncure wrote:
> On Fri, Jul 30, 2010 at 11:01 AM, Yeb Havinga <yebhavinga@gmail.com> wrote:
>   
>> Postgres settings:
>> 8.4.4
>> --with-blocksize=4
>> I saw about 10% increase in performance compared to 8KB blocksizes.
>>     
>
> That's very interesting -- we need more testing in that department...
>   
Definately - that 10% number was on the old-first hardware (the core 2 
E6600). After reading my post and the 185MBps with 18500 reads/s number 
I was a bit suspicious whether I did the tests on the new hardware with 
4K, because 185MBps / 18500 reads/s is ~10KB / read, so I thought thats 
a lot closer to 8KB than 4KB. I checked with show block_size and it was 
4K. Then I redid the tests on the new server with the default 8KB 
blocksize and got about 4700 tps (TPC-B/300)... 67/47 = 1.47. So it 
seems that on newer hardware, the difference is larger than 10%.

regards,
Yeb Havinga