From: <Shaun.Amy_at_email.protected>
Date: Tue, 25 Aug 2009 15:55:36 +1000

Hi Jamie,

Very interesting.

We switched our large filesystems (e.g. 9.5TB on the storage arrays)
to use "xfs" not so much because of performance but rather then
horrific "fsck" times that we have even with filesystems of a few TB
in size.

Regards, Shaun.

>-----Original Message-----
>From: owner-vlbiobs_at_atnf.<!--nospam-->csiro.au [mailto:owner-vlbiobs_at_atnf.<!--nospam-->csiro.au] On
>Behalf Of Jamie Stevens
>Sent: Tuesday, 25 August 2009 3:49 PM
>To: VLBI observers
>Subject: LBA recorder disk speed tests
>
>Hi all,
>
>I've completed some diskspeed tests on cavsi1 using ext3, ext2 and xfs
>filesystems. I did all tests using filesizes that would have been
>generated by an experiment running at 512 Mbit/s; some with 10s files,
>others with 60s files.
>
>I've attached two postscript files to this email. Each shows the results
>of the 9 tests I did, and each file corresponds to tests run on one side
>of the Xraid (all tests were performed on both Xraid sides to ensure
>consistency).
>
>The results show that ext3 is quite a lot slower than ext2 or xfs, even
>when tuned for performance. xfs has the highest average speed, with ext2
>not far behind. It doesn't appear that changing the filesize has much
>effect on the average speed the disks can sustain.
>
>One of the most important things is the minimum speed. The bigbuffer
>will start to fill if the speed falls below the required recording rate,
>and this will lead to bigbuf skips if the disks don't catch up in time.
>ext3 filesystems have a very low minimum speed, as do ext2 filesystems
>with 10s files. But with 60s files, both ext2 and xfs do not drop much
>below 500 Mbit/s, and xfs can keep its minimum rate up even with 10s files.
>
>cheers
>Jamie
Received on 2009-08-25 15:56:25