[MooseFS-Users] Performance issue with mfsmount 3.0.84?

[Wilson, S. M <st...@pu...>]

Hi,


We have several workstations that are using the latest version of mfsmount (3.0.84) and I've started to receive complaints about very slow performance.  I ran a few tests (untarring the Linux kernel source) and it appears that on the 3.0.84 clients performance will continue to degrade each time I run the test.  For example, one workstation shows these results from three successive runs:

?

root@saturn:/net/em/test# time tar xf linux-4.9-rc3.tar; time rm -rf linux-4.9-rc3

real 4m34.614s
user 0m1.416s
sys 0m7.480s

real 2m57.863s
user 0m0.436s
sys 0m2.192s
root@saturn:/net/em/test# time tar xf linux-4.9-rc3.tar; time rm -rf linux-4.9-rc3

real 6m59.159s
user 0m1.924s
sys 0m7.276s

real 5m39.582s
user 0m0.484s
sys 0m2.548s
root@saturn:/net/em/test# time tar xf linux-4.9-rc3.tar; time rm -rf linux-4.9-rc3

real 9m1.816s
user 0m1.928s
sys 0m7.160s

real 7m54.979s
user 0m0.584s
sys 0m2.968s
?
?If I unmount the file system and then mount it again, performance returns to normal but will degrade over time like before.

On the other hand, if I run the same test on a different client using mfsmount 3.0.81 then my performance remains stable and doesn't degrade over time after heavy use.

Is there perhaps a problem with mfsmount versions higher than 3.0.81?

I should add that none of my servers (master, metalogger, chunk) are running higher than 3.0.81 so this could be due to a mismatch between mfsmount and server version.  I doubt this but I wanted to mention it.


Just to mention in passing, the same test on a local disk is blazingly fast in comparison.  I understand that this is a really tortuous test for a distributed file system but the performance discrepancy is quite substantial (5 seconds vs. 275 seconds for the untar, 1 second vs. 178 seconds for the rm).  Here are the timings on the local disk:?

stevew@otter:/otter-scratch/TEST$ time tar xf linux-4.9-rc3.tar; time rm -rf linux-4.9-rc3

real 0m5.419s
user 0m0.304s
sys 0m2.368s

real 0m1.038s
user 0m0.052s
sys 0m0.976s
?

Thanks,


Steve