[Gluster-users] Slow performance from simple tar -x && rm -r benchmark

Chris Webb chris at arachsys.com
Mon Mar 19 09:34:11 UTC 2012

Bryan Whitehead <driver at megahappy.net> writes:

> I didn't see any sync's after the tar/rm commands...

By default, ext4 flushes both metadata and data every five seconds, so a
post-benchmark sync tends to make little difference on a reasonable large test,
but for completeness:

  # time bash -c 'tar xfz ~/linux-3.3-rc7.tgz; sync; rm -rf linux-3.3-rc7; sync'
  real    0m23.826s
  user    0m20.681s
  sys     0m2.392s


  # time bash -c 'tar xfz ~/linux-3.3-rc7.tgz; sync; rm -rf linux-3.3-rc7; sync'

  real    4m24.067s
  user    0m24.692s
  sys     0m7.588s

showing very similar timings and the same effect.

> try using xfs instead of ext4.

I'll build the xfs tooling, add kernel support, and give this a go, but I'm
surprised you think changing the underlying filesystem would eliminate the big
gap between native and gluster performance. I could imagine it improving both
somewhat, but if anything, I'd expect a higher performance filesystem to
amplify the differences. Do you think that glusterfs does something that's
particularly expensive on ext4, much more expensive than the operations proxied
through it?

Best wishes,


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