Hi Niklas!

On Jun 20, 2005, at 10:19 AM, [EMAIL PROTECTED] wrote:

On Sat, 18 Jun 2005, Tom Keiser wrote:


So, can anybody comment on these numbers? Those are dual Opteron
boxes with enough RAM, so please make some suggestions what options I
should try to get more like the real performance of a fileserver...


What kernel? What underlying filesystem?

vanilla 2.4.31, reiserfs.

The performance figures you mentioned when talking directly to the raid, are they when doing IO on a filesystem that are similar to the AFS IO pattern (ie accessing a large number of small files)? Streaming IO figures are more or less uninteresting when doing AFS in our experience.

I haven't had a look yet, but I thought the files were stored also as files in /vicep*? Our files are 1.5GB each, so streaming reads should be what we need, right?

On the other hand I did the read benchmark (dd) with only one process, and the rate went down from 230MB/s to 200MB/s when going through the filesystem instead of reading directly from the block device.

If using ext*, go for ext2 and boot the machine with SMP disabled and se what happens. This improved the situation somewhat for us, but this was on a 2.4 kernel tho (albeit 2.6 is said to still have issues wrt ext3 and SMP).

Disabling SMP is not an option, I'll have to see where tuning the parameters and/or upgrading to 1.3.84 gets me.

Filesystem-wise, xfs seems to be the best performing (and most robust) filesystem on Linux nowadays, but I don't know whether it's supported to have your /vice* on Linux-XFS...

I could try that one, too.

Thanks for your suggestions,
                    Roland

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