Re: Comments requested on IO performance : new db server

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

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