XFS: Abysmal write performance because of excessive seeking (allocation groups to blame?)

[Stan Hoeppner]

On 4/9/2012 4:23 AM, Stefan Ring wrote:
>> Or merely a weak/old product.  The P400 was an entry level RAID HBA,
>> HP's first PCIe/SAS RAID card.  It was discontinued quite some time ago.
>>  The use of DDR2/533 memory indicates it's design stage started probably
>> somewhere around 2004, 8 years ago.
> 
> It was what you got when you bought a direct-attach storage blade from
> HP until a few months ago. Apparently, they changed it to P410i very
> recently: <http://h10010.www1.hp.com/wwpc/us/en/sm/WF06a/3709945-3709945-3710114-3722820-3722776-4304942.html?dnr=1>

Nonetheless, it's performance is quite bad with RAID6 (RAID10 as well).
 If you're happy with EXT4 on the P400 based RAID6, you'll be even much
happier with 3-4x more performance using md for the RAID6.  If it was
worth your time to test the XFS concat I would think this test would be
even more so, as it appears you'll be sticking with EXT4.

-- 
Stan