[Linux-cluster] GFS performance

Ferenc Wagner wferi at niif.hu
Fri Jan 4 16:00:43 UTC 2008


Kamal Jain <kjain at aurarianetworks.com> writes:

> Well, in our applications usage we don't keep cycling over the same
> files over and over again, we run through lots of files and keep a
> handful open at any point in time, so perhaps shorter demote_secs is
> good for us.

It there's no single machine which does most of the accesses, then
probably so.

> I have not been able to find out about 'gfs_controld -l0' -- where
> is that set and what does "-l0" do?

Try gfs_controld -h for some help.  Basically, acquiring of Posix
locks (fcntl locks) is artifically throttled on GFS by default.  If
you invoke gfs_controld with the -l0 option, this throttling is turned
off.  It probably doesn't buy you much unless your application uses
this type of locks.

I hope I recalled the above correctly.  Somebody told me that this
default is likely to be changed in the future, tough.
-- 
Regards,
Feri.




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