Re: [Scst-devel] Tuning scst windows and sw raid5

Re: [Scst-devel] Tuning scst windows and sw raid5

[Chris Weiss]

On Fri, Apr 22, 2011 at 9:08 AM, Łukasz Oleś <lukasz.oles@open-e.com> wrote:
> Hi,
>
> I'm trying to tune Software Raid5, SCST and Windows Initiator to get best
> read/write performance.

My first recommendation is to stick with blockio due to the raid5
write hole possibility when using software raid.

what windows version, and if not server2008, did you align the
partitions? (there's a 2003 and a 2008 R2)

dd is going to use the initiator OS's cache, make sure your test file
size is 2x the ram in the initiator, if not the target too.

Also xfs is much better at dealing with large files than ntfs.  Best
apple to apples test is going to be on raw unformated partitions

I'm not familiar with BST5.  I typically use iometer for both OS's.
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Re: [Scst-devel] Tuning scst windows and sw raid5

[Łukasz Oleś]

On Friday 22 of April 2011 16:19:48 you wrote:
> On Fri, Apr 22, 2011 at 9:08 AM, Łukasz Oleś <lukasz.oles@open-e.com> wrote:
> > Hi,
> > 
> > I'm trying to tune Software Raid5, SCST and Windows Initiator to get best
> > read/write performance.
> 
> My first recommendation is to stick with blockio due to the raid5
> write hole possibility when using software raid.
> 
> what windows version, and if not server2008, did you align the
> partitions? (there's a 2003 and a 2008 R2)
2008 R2

> dd is going to use the initiator OS's cache, make sure your test file
> size is 2x the ram in the initiator, if not the target too.
On initiator I have 2GB RAM and I'm copying 20GB file.

> Also xfs is much better at dealing with large files than ntfs.  Best
> apple to apples test is going to be on raw unformated partitions
What this test(testing on raw partitions) can tell me? In the end I have to 
use filesystem.

> I'm not familiar with BST5.  I typically use iometer for both OS's.
I will try it.

--
Lukasz Oles

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Re: [Scst-devel] Tuning scst windows and sw raid5

[Chris Weiss]

On Fri, Apr 22, 2011 at 9:35 AM, Łukasz Oleś <lukasz.oles@open-e.com> wrote:
> On Friday 22 of April 2011 16:19:48 you wrote:
>> On Fri, Apr 22, 2011 at 9:08 AM, Łukasz Oleś <lukasz.oles@open-e.com> wrote:
>> Also xfs is much better at dealing with large files than ntfs.  Best
>> apple to apples test is going to be on raw unformated partitions
> What this test(testing on raw partitions) can tell me? In the end I have to
> use filesystem.

it'll tell you that scst is being consistent.  there will always be
differences in filesystem performance, try ext3 on linux and you'll
see a huge difference from xfs.
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