Message-ID: <4E4C12BC.9050204@squeakycode.net>
Date: Wed, 17 Aug 2011 14:13:00 -0500
From: Andy Colson <andy@squeakycode.net>
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To: Ogden <lists@darkstatic.com>
CC: pgsql-performance@postgresql.org
Subject: Re: Raid 5 vs Raid 10 Benchmarks Using bonnie++
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	<20110817183101.GJ26302@staff-mud-56-27.rice.edu>
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On 8/17/2011 1:55 PM, Ogden wrote:
>
> 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

I doubt it matters.  The OS is not going to batch delete thousands of 
files.  Once its setup, its pretty constant.  I would not worry about it.

-Andy