[mythtv-users] EXT4 vs XFS

[Tom Hill]

On Sun, 2011-11-13 at 19:01 +0100, Simon Hobson wrote:
> >There's no downside that I know of and you should be able to convert
> >it without reformatting, although it can not be mounted so you may
> >need to use a LiveCD to do it.
> >
> >http://kernelnewbies.org/Ext4#head-3891522e0601162aab24c73c1f148a1e28c6a9d4
> 
> Great. I have enough space to empty one drive, but not the other, so 
> the conversion option is a great help. Unmounting them will be no 
> problem, the recordings are on their own filesystems. 

The conversion doesn't update all files with extents, however. Any speed
benefit is unlikely to be seen, at least initially:

http://www.debian-administration.org/article/Migrating_a_live_system_from_ext3_to_ext4_filesystem

"It may seem that the migration from ext3 to ext4 is now complete, and
it is almost true. Except that any old files created before the
conversion will continue using the bitmap mapping of ext3 instead of
extents of ext4.

Files will eventually migrate to the new format as they are updated
during normal system operation, because on next write they will be saved
using extents. Unfortunately many frequently used files (like
application binaries) are often read and rarely written to. The outcome
is that the files will remain using the old format for a long time, and
you will not be able to experience full potential of ext4."

Tom