Re: /proc/sys/vm/(max|min)-readahead effect????

[Roy Sigurd Karlsbakk]

> thats still does not mean they are sequential creating
> large files almost always causes them to fragment.

ok...
mkfs /dev/hdb1
dd if=/dev/zero of=some-file bs=x count=x

		What can fragment this file????

after that - wget http://localhost/some-file - watch vmstat, and find it's
pushing data at around 28 MB/s

then - start ten wget's retrieving different files, and watch vmstat,
finding the maximum thoughput I can get is ~ 10 MB/s - almost one third.

If I could tell the kernel, the app (tux) or whatever, to do readahead -
say some 4 megs per file, it'd work like hell! Seeks are reduced to a
minimum and everyone's happy again

> Actually does anyone know of an easy way to find out
> if certin files are fragmented and by how much ?

I beleive there used to be a utility called 'frag' or something, to check
the fragmentation of files

roy
--
Roy Sigurd Karlsbakk, MCSE, MCNE, CLS, LCA

Computers are like air conditioners.
They stop working when you open Windows.