Re: Raid 5 vs Raid 10 Benchmarks Using bonnie++

On Wed, Aug 17, 2011 at 03:40:03PM -0500, Ogden wrote:
>
> On Aug 17, 2011, at 1:35 PM, ktm(at)rice(dot)edu wrote:
>
> > On Wed, Aug 17, 2011 at 01:32:41PM -0500, Ogden wrote:
> >>
> >> On Aug 17, 2011, at 1:31 PM, ktm(at)rice(dot)edu wrote:
> >>
> >>> On Wed, Aug 17, 2011 at 01:26:56PM -0500, Ogden wrote:
> >>>> I am using bonnie++ to benchmark our current Postgres system (on RAID 5) with the new one we have, which I have configured with RAID 10. The drives are the same (SAS 15K). I tried the new system with ext3 and then XFS but the results seem really outrageous as compared to the current system, or am I reading things wrong?
> >>>>
> >>>> The benchmark results are here:
> >>>>
> >>>> http://malekkoheavyindustry.com/benchmark.html
> >>>>
> >>>>
> >>>> Thank you
> >>>>
> >>>> Ogden
> >>>
> >>> That looks pretty normal to me.
> >>>
> >>> Ken
> >>
> >> But such a jump from the current db01 system to this? Over 20 times difference from the current system to the new one with XFS. Is that much of a jump normal?
> >>
> >> Ogden
> >
> > Yes, RAID5 is bad for in many ways. XFS is much better than EXT3. You would get similar
> > results with EXT4 as well, I suspect, although you did not test that.
>
>
> i tested ext4 and the results did not seem to be that close to XFS. Especially when looking at the Block K/sec for the Sequential Output.
>
> http://malekkoheavyindustry.com/benchmark.html
>
> So XFS would be best in this case?
>
> Thank you
>
> Ogden

It appears so for at least the Bonnie++ benchmark. I would really try to benchmark
your actual DB on both EXT4 and XFS because some of the comparative benchmarks between
the two give the win to EXT4 for INSERT/UPDATE database usage with PostgreSQL. Only
your application will know for sure....:)

Ken