holland-coredev team mailing list archive

[Andrew Garner <1296854@xxxxxxxxxxxxxxxxxx>]

Public bug reported:

NFS mounted with async does not immediately free the space on unlink().
I.e. unlink() does not block until the space is actually freed on the
server and is instead freed in the background.

When paired with purge-policy=before-backup and estimation, the
estimation part fails even if holland technically purged out enough
data.   NFS is still purging in the background when we calculate
estimation so the space isn't actually freed.

I am not sure if there is a good solution here.  Both 'rm -f' and
python's shutil.rmtree give the same results.   I was hoping perhaps a
fileobj.truncate(0) + os.fsync() might work around this, but that does
not appear to be the case.   fsync does not block until this io is
complete, unfortunately :(  I suppose we could inject some (optional)
sleep logic here.  Maybe there's some better way to monitor that the
unlink is actual complete. :-\

** Affects: holland-backup
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1296854

Title:
  NFS backup_directory + purging is broken

Status in Holland Backup Framework:
  New

Bug description:
  NFS mounted with async does not immediately free the space on
  unlink().  I.e. unlink() does not block until the space is actually
  freed on the server and is instead freed in the background.

  When paired with purge-policy=before-backup and estimation, the
  estimation part fails even if holland technically purged out enough
  data.   NFS is still purging in the background when we calculate
  estimation so the space isn't actually freed.

  I am not sure if there is a good solution here.  Both 'rm -f' and
  python's shutil.rmtree give the same results.   I was hoping perhaps a
  fileobj.truncate(0) + os.fsync() might work around this, but that does
  not appear to be the case.   fsync does not block until this io is
  complete, unfortunately :(  I suppose we could inject some (optional)
  sleep logic here.  Maybe there's some better way to monitor that the
  unlink is actual complete. :-\

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