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

Joe Landman
2012-04-10T14:32:48Z

On 04/10/2012 10:02 AM, Stefan Ring wrote:
>> And is XFS aligned to the RAID 6?
>>
>> What does xfs_info display on it?
>
> Yes, it’s aligned.
>
> meta-data=/dev/mapper/vg_data-lvhome isize=256 agcount=4,
> agsize=73233656 blks
> = sectsz=512 attr=2
> data = bsize=4096 blocks=292934624, imaxpct=5
> = sunit=8 swidth=32 blks
> naming =version 2 bsize=4096 ascii-ci=0
> log =internal bsize=4096 blocks=143040, version=2
> = sectsz=512 sunit=8 blks, lazy-count=1
> realtime =none extsz=4096 blocks=0, rtextents=0
>
> I changed the stripe size to 32kb in the meantime. This way, it
> performs slightly better.

try 128k to 512k for stripe size. And try to increase your agcount by
(nearly) an order of magnitude.

--
Joseph Landman, Ph.D
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