[K12OSN] Impact of filesystems on performance

[Les Mikesell]

On Thu, 2004-03-25 at 15:23, Eric Feldhusen wrote:
>  ...just watching the throughput when copying a couple of
> gigabytes of files while users logging in and out 
> and moving their windows profiles back and forth, I see
> the file system  really slow down.

Linux buffers everything on a least-recently-used basis.
If you copy some huge amount of files (relative to your
free/buffer RAM) you will force everything else out of
buffer.  Then you have to wait for the disk head to go
get it again the next time you need it on the read side
and on the write side things have to wait for buffers to
be flushed and freed.  Different file systems can make
some small difference in disk head optimization, but for
big differences you either need to spread the activity
across more independent disks or throw more RAM at it.

---
  Les Mikesell
   les at futuresource.com