MD1000 and PERC5/E I/O bottleneck

Vincent Janelle Vincent.Janelle at active.com
Mon Jun 4 09:00:36 CDT 2007


You're hitting the upper limits of pci-e right now, its limited to 2.5
gigabits per second.. I think.

You might also want to check the block size that you're making your file
system with, that might give you some better I/O.

-----Original Message-----
From: Eric Yablonowitz [mailto:eyablon at tripadvisor.com] 
Sent: Monday, June 04, 2007 5:32 AM
To: Vincent Janelle
Cc: Peter Verhoeven; linux-poweredge at dell.com
Subject: Re: MD1000 and PERC5/E I/O bottleneck

full MD1000 w/ 15K RPM SAS HDDs.

On Jun 4, 2007, at 12:22 AM, Vincent Janelle wrote:

> Are these sata disks, or sas?
>
> -----Original Message-----
> From: linux-poweredge-bounces at dell.com
> [mailto:linux-poweredge-bounces at dell.com] On Behalf Of Eric  
> Yablonowitz
> Sent: Sunday, June 03, 2007 6:37 PM
> To: Peter Verhoeven
> Cc: linux-poweredge at dell.com
> Subject: Re: MD1000 and PERC5/E I/O bottleneck
>
> RAID-1 (inherently 2 disks) offers much less write throughput than a
> 7 disk RAID-5 on the PERC-5 in my tests.  RAID-10 on 6 disks was
> closer, but still (somewhat surprisingly) slower than RAID-5 on 7  
> disks.
>
> On Jun 3, 2007, at 9:21 PM, Peter Verhoeven wrote:
>
>> Can you afford to go with RAID-1 instead of RAID 5?
>>
>>
>> -----Original Message-----
>> From: linux-poweredge-bounces at dell.com
>> [mailto:linux-poweredge-bounces at dell.com] On Behalf Of Eric
>> Yablonowitz
>> Sent: Saturday, 2 June 2007 9:03 AM
>> To: linux-poweredge at dell.com
>> Subject: MD1000 and PERC5/E I/O bottleneck
>>
>> So these results imply that there is a bottleneck somewhere that is
>> preventing me from getting anywhere near what my 14 spindles can
>> handle.
>> Any thoughts on what this bottleneck might be?
>>
>> Thanks,
>> Eric
>>
>





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