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

On Aug 17, 2011, at 1:48 PM, Andy Colson wrote:

> On 8/17/2011 1:35 PM, ktm@rice.edu wrote:
>> On Wed, Aug 17, 2011 at 01:32:41PM -0500, Ogden wrote:
>>> 
>>> On Aug 17, 2011, at 1:31 PM, ktm@rice.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.
>> 
>> Regards,
>> Ken
>> 
> 
> A while back I tested ext3 and xfs myself and found xfs performs better for PG.  However, I also have a photos site with 100K files (split into a small subset of directories), and xfs sucks bad on it.
> 
> So my db is on xfs, and my photos are on ext4.


What about the OS itself? I put the Debian linux sysem also on XFS but haven't played around with it too much. Is it better to put the OS itself on ext4 and the /var/lib/pgsql partition on XFS?

Thanks

Ogden