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Re: Comments requested on IO performance : new db server

From: Rory Campbell-Lange <rory(at)campbell-lange(dot)net>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Comments requested on IO performance : new db server
Date: 2012-03-10 10:51:12
Message-ID: 20120310105112.GB9760@campbell-lange.net (view raw or flat)
Thread:
Lists: pgsql-performance
Is a block size of 4096 a good idea both for the filesystem and
postgresql? The analysis here:
http://www.fuzzy.cz/en/articles/benchmark-results-hdd-read-write-pgbench/ 
appears to suggest that at least for database block sizes of 4096
read/write performance is much higher than for smaller block sizes.

Rory

On 09/03/12, Rory Campbell-Lange (rory(at)campbell-lange(dot)net) wrote:
> ...An ancillary question is whether a 4096 block size is a good idea.
> I suppose we will be using XFS which I understand has a default block
> size of 4096 bytes. 
> 
> RAID 10
> --------------------------------------
> Read sequential
> 
>     BS           MB/s             IOPs
>    512        0129.26        264730.80
>   1024        0229.75        235273.40
>   4096        0363.14        092965.50
>  16384        0475.02        030401.50
>  65536        0472.79        007564.65
> 131072        0428.15        003425.20
> --------------------------------------
> Write sequential
> 
>     BS           MB/s             IOPs
>    512        0036.08        073908.00
>   1024        0065.61        067192.60
>   4096        0170.15        043560.40
>  16384        0219.80        014067.57
>  65536        0240.05        003840.91
> 131072        0243.96        001951.74
> --------------------------------------
> Random read
> 
>     BS           MB/s             IOPs
>    512        0001.50        003077.20
>   1024        0002.91        002981.40
>   4096        0011.59        002968.30
>  16384        0044.50        002848.28
>  65536        0156.96        002511.41
> 131072        0170.65        001365.25
> --------------------------------------
> Random write
> 
>     BS           MB/s             IOPs
>    512        0000.53        001103.60
>   1024        0001.15        001179.20
>   4096        0004.43        001135.30
>  16384        0017.61        001127.56
>  65536        0061.39        000982.39
> 131072        0079.27        000634.16
> --------------------------------------
-- 
Rory Campbell-Lange
rory(at)campbell-lange(dot)net

Campbell-Lange Workshop
www.campbell-lange.net
0207 6311 555
3 Tottenham Street London W1T 2AF
Registered in England No. 04551928

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Subject: Re: Comments requested on IO performance : new db server
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