Re: 3ware 9650 tips

Justin Piszcz
2007-07-13T19:36:50Z

On Fri, 13 Jul 2007, Jon Collette wrote:

> Wouldn't Raid 6 be slower than Raid 5 because of the extra fault tolerance?
> http://www.enterprisenetworksandservers.com/monthly/art.php?1754 - 20%
> drop according to this article
>
> His 500GB WD drives are 7200RPM compared to the Raptors 10K. So his numbers
> will be slower.
> Justin what file system do you have running on the Raptors? I think thats an
> interesting point made by Joshua.

I use XFS:

Justin what file system do you have running on the Raptors? I think thats
an interesting point made by Joshua.

But I also run several 'optimations' for SW RAID and my overall
configuration-- However, for the mkfs.xfs options, they auto-optimize for
whatever (SW) raid I have them configured for. Whereas if XFS cannot tell
the disks/etc underneath the HW raid, I do not think the optimizations
will be present(?)-- which menas you'd have to set the sunit and swidth
appropriately.

>
>
> Justin Piszcz wrote:
>>
>>
>> On Fri, 13 Jul 2007, Joshua Baker-LePain wrote:
>>
>>> My new system has a 3ware 9650SE-24M8 controller hooked to 24 500GB WD
>>> drives. The controller is set up as a RAID6 w/ a hot spare. OS is CentOS
>>> 5 x86_64. It's all running on a couple of Xeon 5130s on a Supermicro
>>> X7DBE motherboard w/ 4GB of RAM.
>>>
>>> Trying to stick with a supported config as much as possible, I need to run
>>> ext3. As per usual, though, initial ext3 numbers are less than
>>> impressive. Using bonnie++ to get a baseline, I get (after doing 'blockdev
>>> --setra 65536' on the device):
>>> Write: 136MB/s
>>> Read: 384MB/s
>>>
>>> Proving it's not the hardware, with XFS the numbers look like:
>>> Write: 333MB/s
>>> Read: 465MB/s
>>>
>>> How many folks are using these? Any tuning tips?
>>>
>>> Thanks.
>>>
>>> --
>>> Joshua Baker-LePain
>>> Department of Biomedical Engineering
>>> Duke University
>>>
>>
>> Let's try that again with the right address :)
>>
>>
>> You are using HW RAID then? Those numbers seem pretty awful for that
>> setup, including linux-raid@ even it though it appears you're running HW
>> raid,
>> this is rather peculiar.
>>
>> To give you an example I get 464MB/s write and 627MB/s with a 10 disk
>> raptor software raid5.
>>
>> Justin.
>>
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