Re: Raid 5 vs Raid 10 Benchmarks Using bonnie++ - Mailing list pgsql-performance

From Ogden
Subject Re: Raid 5 vs Raid 10 Benchmarks Using bonnie++
Date
Msg-id AE7D7AD5-0948-438E-BA75-E12A8EB44446@darkstatic.com
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In response to Re: Raid 5 vs Raid 10 Benchmarks Using bonnie++  (Gary Doades <gpd@gpdnet.co.uk>)
Responses Re: Raid 5 vs Raid 10 Benchmarks Using bonnie++  (Gary Doades <gpd@gpdnet.co.uk>)
List pgsql-performance
On Aug 17, 2011, at 1:33 PM, Gary Doades wrote:

> On 17/08/2011 7:26 PM, Ogden wrote:
>> I am using bonnie++ to benchmark our current Postgres system (on RAID 5) with the new one we have, which I have
configuredwith RAID 10. The drives are the same (SAS 15K). I tried the new system with ext3 and then XFS but the
resultsseem really outrageous as compared to the current system, or am I reading things wrong? 
>>
>> The benchmark results are here:
>>
>> http://malekkoheavyindustry.com/benchmark.html
>>
> The results are not completely outrageous, however you don't say what drives, how many and what RAID controller you
havein the current and new systems. You might expect that performance from 10/12 disks in RAID 10 with a good
controller.I would say that your current system is outrageous in that is is so slow! 
>
> Cheers,
> Gary.


Yes, under heavy writes the load would shoot right up which is what caused us to look at upgrading. If it is the RAID
5,it is mind boggling that it could be that much of a difference. I expected a difference, now that much.  

The new system has 6 drives, 300Gb 15K SAS and I've put them into a RAID 10 configuration. The current system is ext3
withRAID 5 over 4 disks on a Perc/5i controller which has half the write cache as the new one (256 Mb vs 512Mb).  

Ogden

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