Re: suggestions for postgresql setup on Dell 2950 , PERC6i controller

On Wed, Feb 18, 2009 at 12:52 AM, Rajesh Kumar Mallah
<mallah(dot)rajesh(at)gmail(dot)com> wrote:
> the raid10 voulme was benchmarked again
> taking in consideration above points

> Effect of ReadAhead Settings
> disabled,256(default) , 512,1024
>
> xfs_ra0 414741 , 66144
> xfs_ra256 403647, 545026 all tests on sda6
> xfs_ra512 411357, 564769
> xfs_ra1024 404392, 431168
>
> looks like 512 was the best setting for this controller

That's only known for sequential access.
How did it perform under the random access, or did the numbers not
change too much?

> Considering these two figures
> xfs25 350661, 474481 (/dev/sda7)
> 25xfs 404291 , 547672 (/dev/sda6)
>
> looks like the beginning of the drives are 15% faster
> than the ending sections , considering this is it worth
> creating a special tablespace at the begining of drives

It's also good because you will be short stroking the drives. They
will naturally have a smaller space to move back and forth in and this
can increase the random speed access at the same time.