Date: Thu, 28 Jul 2005 15:46:55 -0400 From: Bob Johnson <bob89@eng.ufl.edu> To: Lowell Gilbert <freebsd-questions-local@be-well.ilk.org> Cc: Victor Semionov <victor@vmpbg.com>, freebsd-questions@freebsd.org Subject: Re: defragmentation in FreeBSD 4.11 Message-ID: <200507281546.56214.bob89@eng.ufl.edu> In-Reply-To: <44ll3qu4v3.fsf@be-well.ilk.org> References: <200507281157.42688.bob89@eng.ufl.edu> <44ll3qu4v3.fsf@be-well.ilk.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thursday 28 July 2005 03:07 pm, Lowell Gilbert wrote: > Bob Johnson <bob89@eng.ufl.edu> writes: > > From: Victor Semionov <victor@vmpbg.com> [...] > > > Why is it unnecessary to defragment UFS? > > > > In normal use, files never become fragmented enough to affect > > performance. In a (loose) sense, files are intentionally fragmented in a > > controlled way so that fragmentation doesn't cause problems. If you run > > fsck on a partition, you will typically see fragmentation levels of less > > than one percent. > > Careful, there; "fragmentation" on a UFS is measuring a completely > different thing than the same term applied to a Microsoft filesystem. > For UFS, it refers to non-contiguous free blocks (fragments, > actually), as opposed to the Microsoft terminology, where it refers to > non-contiguous blocks within the same file. > > Everything you are saying is correct, but it will confuse people who > don't realize the difference. Yeah, I was trying to keep a long response from getting even longer. And I didn't really know what fsck is measuring when it reports fragmentation, so I got lazy and glossed over it instead of digging up the information. Thanks for keeping me honest, - Bob
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200507281546.56214.bob89>