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[Bug 601299] Re: btrfs fsync() is extremely slow

 

** Tags added: utopic

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https://bugs.launchpad.net/bugs/601299

Title:
  btrfs fsync() is extremely slow

Status in “linux” package in Ubuntu:
  Confirmed
Status in “linux” source package in Maverick:
  Won't Fix

Bug description:
  Installation and upgrades on btrfs are *extremely* slow.  This is
  because dpkg makes extensive fsync() calls to make sure that a power
  loss in the middle of an operation does not leave the system in a
  broken state.  These calls have a significant performance penalty on
  other filesystems ( such as ext[234] ), but on btrfs, the penalty is
  multiple orders of magnitude.

  As a workaround, you can use the eatmydata package/command around dpkg
  /apt-get to disable the fsync() calls and restore good performance
  during upgrades, at the risk of hosing the system if it crashes.  The
  apt-btrfs-snapshot package will have apt make a snapshot before it
  begins an upgrade so that if things do go wrong, you can at least roll
  back to the snapshot.

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