[mythtv-users] Does JFS filesystem need defragment?

George Mari george_mythusers at mari1938.org
Sat Nov 10 16:51:11 UTC 2007

Ismo Tanskanen wrote:
> I use JFS file system for myth recordings, because it's ability to 
> delete files quickly.
> Now I'm wondering, if it needs defragment time to time? Does it? Is 
> there any utility to do that?
> Or is there better filesystem for myth recordings?

I use JFS for my recordings as well.  I've done some research and was 
not able to find any defragging utility that would work with JFS.

I've also not found any evidence that JFS needs to be defragmented.

I run FC6, so I grabbed the e2fsprogs package which includes the 
filefrag utility.  You can point the filefrag utility at your recordings 
directory and it will tell you how many extents (fragments) each file is 
stored in.  My filesystem is pretty full, so most of my recordings are 
fragmented in 2 to 12 fragments.  With this level of fragmentation I 
don't notice any performance issues.

If you really want to defragment your JFS filesystem, you could move all 
your files off the filesystem, delete them from the original location, 
and then copy them back.

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