Steven Whitehouse <swhiteho@xxxxxxxxxx> writes: > If you are worried about read I/O, then I'd look carefully at the > fragmentation using filefrag on a few representative files to see how > they are laid out on disk. A running qcow2 image, using a backing file: - running qcow2 is 822MB with 3002 extents - backing file is 2.2GB with 2893 extents Another saved images, used as read-only backing file for running VMs is 7.5GB with 9640 extents. > There are other possible causes of > performance issues too - do you have the fs mounted noatime (which we > recommend for most use cases) for example? Right, I missed that one, I need to planify a down time. > Running a filesystem which is close to the capacity limit can generate > fragmentation over time, 80% would usually be ok, and more recent > versions of GFS2 are better than older ones at avoiding fragmentation > in such circumstances, It's running on Ubuntu Trusty a 3.13 kernel and gfs2-utils 3.1.6. Thanks. -- Daniel Dehennin Récupérer ma clef GPG: gpg --recv-keys 0xCC1E9E5B7A6FE2DF Fingerprint: 3E69 014E 5C23 50E8 9ED6 2AAD CC1E 9E5B 7A6F E2DF
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