On Fri, Apr 20, 2001 at 04:54:57PM -0300, Peter Cordes wrote: > On Fri, Apr 20, 2001 at 11:14:35AM -0700, Jeff Coppock wrote: > > I was wondering if it's necessary to defragment ext2fs or reiserfs? I do > > this on a regular basis with my Windoze machines. > > > > What utilities could be used for this, if it's recommended? > > ext2 is smart, and does a good job of not fragmenting files. search the > web, lots of good info is out there. Reiserfs is also smart like that. > (BTW, it's the allocation algorithms in particular that are smart. They put > new files where they will have room to grow without fragmenting.) > > If you have an almost-full filesystem, there won't be room to avoid > fragmentation, so you should avoid that. ext2 is most efficient when less > than 90% full, or so. (I don't know what a good cutoff value should be, but > 90% is probably reasonable.) > > There is an ext2defrag or something around, so you can use that if you want > to. Most people never defrag their FSes, and have no problems with them.
My own experiences with defragging ext2 have generally been: Don't. On the other hand, if you happen to shrink an ext2 partition with some utility like Partition Magic (and I haven't tried ext2 resize yet) it'll actually help to run a defrag on it afterward. On the other hand, you can't quit in the middle of defragging, and you can't defrag the current root partition. -- Ferret who learned the hard way, when the power failed during a defrag once.
