RAID10 stripe size and PostgreSQL performance

[Ivan Voras]

On 08/07/2013 14:40, Artem Naluzhnyy wrote:
> Hi,
> 
> I'm benchmarking PostgreSQL using different RAID10 stripe size values
> for a new server. Tried bonnie++ and pgbench on two stripe size
> configurations:
> 
>   * 32 KB (a half of current UFS bsize) - 254 pgbench tps
>   * 1 MB (max supported by the RAID controller) - 626 pgbench tps
> 
> See OS/hardware configuration, benchmark methodology and raw results
> here - http://pastebin.com/F8uZEZdm
> 
> Is this expected behavior with more than twice higher pgbench tps on
> 1MB stripe size?

No, it is not.

For start, can you please repeat your benchmarks but with restarting the
PostgreSQL server between each pgbench run?

Also, you should make sure that the database is located on the same
location on the disk platters by e.g. creating a small partition which
is about 150% larger than your pgbench database (and your pgbench
database should be at least 2x larger than your RAM, if you are going to
benchmark IO and not memory caches), which is located at the same
position (byte offset) in your RAID10 volume.


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