[Lustre-devel] LustreFS performance

Andreas Dilger adilger at sun.com
Mon Mar 2 12:45:01 PST 2009


On Mar 02, 2009  20:04 +0300, Vitaly Fertman wrote:
>    RAM: enough to have a tmpfs for MDS;
 
Note that strictly speaking we need to use ldiskfs on a ramdisk, not
tmpfs, because we don't have an fsfilt_tmpfs.

> Q:  which raid?
> A: raid5, as it seems to be the most popular.

I would propose:
- for MDT it needs to be RAID-1+0, because of small, random IO sizes
- for OST it needs to be RAID-6, because of double-failure risk (see
  Lustre Manual "RAID" section for discussion)

> **** Statistics ****
> 
> During all the tests the following is supposed to be running on all  
> the servers:
> 1) vmstat
> 2) iostat, if there is some disk activity.
> smth else?

I would propose either LLNL's LMT or HP's collectl, which both also
collect Lustre stats.  Those both provide more information than the
above, and having the IO/CPU load correlated to Lustre RPC counts is
very useful.

> MDST3
> 
> Q: do we want to test stat(2) with other then tmpfs disk on OST?
> what journal should it have if so?

I would be quite interested in the performance numbers from just
the ramdisk MDT+OST, to see what the upper limit of the protocol
and network are.

> 9. find
> Q: despite the fact we currently have a large downgrade with
> "find -f type", do we want to have this test in the general test set?

Some of that performance loss should have been fixed recently.  We
should continue to test it.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.




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