[mythtv-users] Performance issues with ext4

Daniel Kristjansson danielk at cuymedia.net
Sun Dec 27 19:45:43 UTC 2009

I sounds like you had performance issues with mysql on ext4.
I'm not aware of any such problems which are not shared by ext3.
It may have just been the ext4 file system creation params are
different in your distro for ext3 and ext4. XFS beats both handily
for mysql performance. But I'm actually using ext3 her for mysql
tables because XFS clears all open files on a crash, while I prefer
to have them in an intermediate state so mysql can attempt recovery.

For video I've been testing ext4 for some months and it is much
better than ext3. But since the online defragmenting for ext4
is still scary experimental, XFS with a nightly defrag is still
the preferred option for video mounts. If you wish to use a
non-XFS filesystem for MythTV it is best to tell it to reserve
enough space for a few recordings, say 20GB, since completely
filling a disk defeats even the best allocation algorithms and
causes fragmentation.

-- Daniel 

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