Hi, All
--
I'm playing around
with FC4 (x86_64smp - Dell PowerEdge 1850 hardware) and the GFS rpms included in
the distribution. Couple of questions:
I know that there's
a list of tunable options given by gfs_tool gettune <mountpoint>. Is
there a list somewhere of what these options do?
Is there a way to
optimize GFS with regards to opening/closing files with fnctl locks?
My app does a lot of writing with fnctl locks (file-based database application),
and it really drags on GFS when running distributed locks. I've posted
about this in the past; I'm just now getting around to looking at GFS
again. I haven't seen a problem with regards to actual I/O
throughput over my iSCSI SAN - my app under GFS typically will do 30
kB/s, and I have been able to push 100+ MB/s through the SAN - it's
just slowing down significantly when the files are opened with a fnctl
lock. The top command gives the following:
PID
USER PR NI VIRT RES SHR S
%CPU %MEM TIME+ COMMAND
5996 root 18 0 4268 2700 1564 R 39.8 0.1 0:01.20 runcobol
3201 root 10 -5 0 0 0 S 22.9 0.0 8:20.86 dlm_astd
4285 root 10 -5 0 0 0 S 15.9 0.0 0:43.59 lock_dlm2
4284 root 10 -5 0 0 0 S 13.9 0.0 0:44.91 lock_dlm1
5996 root 18 0 4268 2700 1564 R 39.8 0.1 0:01.20 runcobol
3201 root 10 -5 0 0 0 S 22.9 0.0 8:20.86 dlm_astd
4285 root 10 -5 0 0 0 S 15.9 0.0 0:43.59 lock_dlm2
4284 root 10 -5 0 0 0 S 13.9 0.0 0:44.91 lock_dlm1
I've seen dlm_astd
and the two lock processes go higher than this in CPU time, sometimes up to
30%+.
For some reason I
remember reading somewhere that I should disable hyperthreading when using
GFS. I can't seem to find where I read that statement. Am I'm just
going insane, or is that really the recommendation?
We'd like to see
three or more of the machines in the mix; currently there is only one. Any
suggestions would be greatly appreciated.
Thanks!
--Peter
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