Re: EXT4 is ~2X as slow as XFS (593MB/s vs 304MB/s) for writes?

From: Michael Tokarev
Date: Mon Mar 01 2010 - 09:48:24 EST

Justin Piszcz wrote:
> On Mon, 1 Mar 2010, Andreas Dilger wrote:
>> On 2010-02-28, at 07:55, Justin Piszcz wrote:
>> Have you tried testing with "nice" numbers of disks in your RAID set
>> (e.g. 8 disks for RAID-0, 9 for RAID-5, 10 for RAID-6)? The mballoc
>> code is really much better tuned for power-of-two sized allocations.
> Hi,
> Yes, the second system (RAID-5) has 8 disks and it shows the same
> performance problems with ext4 and not XFS (as shown from previous
> e-mail), where XFS usually got 500-600MiB/s for writes.
> For the RAID-5 (from earlier testing): <- This one has 8 disks.

Note that for RAID-5, the "nice" number of disks is 9 as Andreas
said, not 8 as in your example.

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