[mythtv-users] Defrag older Myth EXT3 filesystem

[Joseph Fry]

> Thought I should start a new thread on this question.  I am having
> problems with my older Myth 0.21 system running on Mythbuntu 8.04.  It has
> EXT3 file systems.  It was suggested that my problem could be solved by
> defragmenting the drives.
>
> How do you measure fragumention level?
> How do you defragment?  Can it even be done?  I see that the latest
> Mythbuntu install uses EXT4, which apparently has defrag built in.
>

To check fragmentation, see the link below.

There is no Ext3 defrag tool that works on the filesystem level... but
there are lots of ways to take advantage of the filesystem's method of
preventing fragmentation.

Essentially, if the file system has enough space to hold an entire file, it
will reserve this space during the write.  Unfortunately because recordings
grow rather than being written whole, they can often become fragmented
because the file system cannot reserve space to hold the entire file.

To "defrag" the file, simply create a copy of it and delete the original.
 This only works well if the drive is not very full because there may not
be enough contiguous free space to hold the new file in a filesystem that
is nearly full, or was recently full with streamed data like recordings.

Even better would be to move all of your recordings to an external drive,
then move them back.

Finally you can automate this 'defrag' with something like shake:
http://www.webupd8.org/2009/10/defragmenting-linux-ext3-filesystems.htmlwhich
ultimately does something very similar to the above file copy.
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