Mike McCarty wrote:
Jim Cornette wrote:
John Summerfied wrote:
Jeff Vian wrote:
Exactly, and IIRC the filesystem knows that if it needs X amount of
space for a file, then Y number of inodes are marked for use for that
file at the beginning. Thus space allocated is as contiguous as is
efficient for read/write on the disk.
If "the filesystem knows that if it needs X amount of space for a
file," that implies there's a way of telling it that.
How's that done? I don't recall any system call for *x (there is one
for OS/2), and one could do it in JCL in IBM's OS in the 60s), but
in the *x world I've never seen a way to do it.
Since the discussions regarding fragmentation on ext3 filesystems was
pretty long running. I decided to try
filefrag /usr/bin/* |sort |grep 'would be'
and the output showed a lot of fragmentation. One of the files was up
to 45.
On my system I did this...
# filefrag /usr/bin/* | sort -k2 -nr | grep 'would be'
Here're the first few entries...
/usr/bin/emacs: 248 extents found, perfection would be 1 extent
/usr/bin/emacs-21.3: 248 extents found, perfection would be 1 extent
/usr/bin/kermit: 80 extents found, perfection would be 1 extent
/usr/bin/kbabel: 45 extents found, perfection would be 1 extent
/usr/bin/ddd: 45 extents found, perfection would be 1 extent
/usr/bin/gthumb: 41 extents found, perfection would be 1 extent
/usr/bin/gdbtui: 36 extents found, perfection would be 1 extent
/usr/bin/elinks: 30 extents found, perfection would be 1 extent
/usr/bin/iniomega: 22 extents found, perfection would be 1 extent
/usr/bin/kpersonalizer: 21 extents found, perfection would be 1 extent
/usr/bin/artsd: 21 extents found, perfection would be 1 extent
/usr/bin/artscat: 20 extents found, perfection would be 1 extent
/usr/bin/kiconedit: 19 extents found, perfection would be 1 extent
/usr/bin/glade-2: 19 extents found, perfection would be 1 extent
/usr/bin/karm: 18 extents found, perfection would be 1 extent
/usr/bin/dia: 18 extents found, perfection would be 1 extent
/usr/bin/designer3: 18 extents found, perfection would be 1 extent
/usr/bin/designer: 18 extents found, perfection would be 1 extent
/usr/bin/kppplogview: 16 extents found, perfection would be 1 extent
/usr/bin/kfontinst: 16 extents found, perfection would be 1 extent
/usr/bin/civclient-xaw: 15 extents found, perfection would be 1 extent
/usr/bin/cdrecord: 15 extents found, perfection would be 1 extent
/usr/bin/knewstickerstub: 14 extents found, perfection would be 1 ext
Surely those who argue that ext3 does not get fragmented
during install don't think that 248 extents is "not
significant fragmentation".
I assure you that I have done nothing on my system to try to
fragment emacs.
Mike
The fragmentation for your emacs is unbelievably high. I did not find
anything yet fragmented in the hundreds, let alone several hundred
extents. Are you using LVM? My system is setup in traditional
partitions. LVM usage "seemed" slower in responsiveness, so I assumed it
was more in fragments
Jim
