[lug] defragging

[Jeffrey B. Siegal]

It generally isn't needed; Linux does a pretty good job of keeping the
file system naturally unfragmented.  But if you are radically
reorganizing your file systems, you might as well backup the files,
recreate you file systems and restore all the files.

One thing that helps reduce fragmentation a little is to use a block
size of 4096 rather than the default of 1024 when creating the file
system. (Use the -b option on mke2fs.)  This will increase overhead for
small files though.