[OpenAFS] Perfomance

FBO fbo2@gmx.net
Mon, 20 May 2002 21:17:33 +0200

On Mon, May 20, 2002 at 11:16:59AM -0500, Charles Clancy wrote:
> Other benchmarks: 4.6MBps between partitions of a normal local UNIX
> filesystem.  40MBps from local to /tmp.
What does "local to /tmp" mean? Is your /tmp non-local?

> Are we talking 3200 RPM IDE or 7200 RPM IDE?  If it's the former, that's
> probably your slowdown.  See how fast you can copy between partitions
> locally.  Having a 100 Mbps switch does you no good when your IDE bus is
> only running at 15 Mbps.
I do use 5400-IDE-Drives (UDMA) only. A local filecopy shows 7.2MByte/s but
copying from a local afs-volume to a local unix-path (on a P-200)
is always a bit below 2MB/s.

> > I was told that the cachemanager could be the problem. Is there a chance
> > to bybass it (at least for accessing the local subnet)?
> We've had this discussion before.  First of all, it would involve major
> changes to the way the AFS client works.  Second, you'd have cache
> consistancy problems with other AFS clients if one client didn't have a
> cache.
Does this imply, using a Cache-FS on RamDisk (which is definitly deleted
when rebooting) is critical?
Again: 3MB/s means using a Ramdisk as cache-fs. Using a real hdd-partition
       means to be limited to about 600kB/s (at least for my PC)