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

[Emmanuel Florac]

Le Sun, 08 Apr 2012 15:33:01 -0500 vous écriviez:

> > 
> > From my experience, with modern arrays don't make much of a
> > difference. I've reached decent IOPS (i. e. about 4000 IOPS) on
> > large arrays of up to 46 drives provided there are enough threads
> > -- more threads than spindles, preferably.  
> 
> Are you speaking of a mixed metadata/data heavy IOPS workload similar
> to that which is the focus of this thread, or another type of
> workload?  Is this 46 drive array RAID10 or RAID6?

Pure random access, 8K IO benchmark (database simulation). RAID-6
performs about the same in pure reading tests, but stinks terribly at
writing of course.

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