On Fri, 2005-12-30 at 10:10 -0600, Mike McCarty wrote:
> Again, the point was that some claim that ext3 does not and will
> not fragment files which are not dynamic. I claimed that fragmentation
> can occur simply due to install of software, which some claimed
> will not and does not occur with ext3. I think that I have demonstrated
> my point. In fact, I was quite shocked that it was as bad as that,
> frankly.
Hi Mike,
OK, fragmentation can and sometimes does occur. You've explained why
and how.
So the next logical question is: what difference, if any, does it make?
Can you or anyone else come up with a way to measure the effect or some
aspect of it? Perhaps a benchmark that shows how application startup
times suffer?
I'm not a filesystems guru, but even so its not at all clear to me that
fragmentation must necessarily cause a big or repeated performance hit.
Given Linux's VM, it seems plausible that an initial file load might
suffer (maybe a lot or maybe a tiny bit?) and that subsequent file
accesses will be from pages already cached in RAM.
We should all keep open minds and, if possible, generate some actual
benchmark data!
Ed
--
Edward H. Hill III, PhD
office: MIT Dept. of EAPS; Rm 54-1424; 77 Massachusetts Ave.
Cambridge, MA 02139-4307
emails: eh3@xxxxxxx ed@xxxxxxx
URLs: http://web.mit.edu/eh3/ http://eh3.com/
phone: 617-253-0098
fax: 617-253-4464
