[mythtvnz] convert ext3 to xfs?

[David Shepherd]

Just upgraded my myth backend with a 250GB drive but it looks like I've
chosen the wrong disk format.
I went with the standard ext3 option and now find it takes ~5-10secs to
delete a 2GB recording during which time the frontend is unusuable. 

>From the reading I've done it looks like xfs would have been a better
choice.  Has anyone successfully converted a drive from ext3 to xfs
apart from the obvious reformat and re-install method?

I'd also welcome any advice on how to partition a drive this size.  I'm
using Debian Testing so I guess I have some freedom on where to put
recordings, videos, music etc.

Thanks
Dave