[OpenAFS] AFS Speed

[Nathan Ward]

I have an AFS cell, which has a single fileserver and a bunch of 
workstations.

The fileserver has ~180Gb of storage, which achieves ~60Mb/sec when 
writing directly to an ext2 partition.

 From all my client machines, the access speeds to the AFS server are 
shocking. Deleting a tree that is ~25Mb of source files (ie smallish 
files) takes upward of 30 minutes, and there appears to be very little 
CPU load on the server and client machines during this time...

Reading that tree takes a long time (I dont have any figures right now), 
but not as long as writing or deleting.

It seems that all the fileserver processes are at about 0.1-0.9% CPU, 
and are almost always sleeping.

Network speed is not an issue, as there is full gigE between the 2 machines.

I originally attributed this to the fact that AFS has its own databases 
etc and manipulating them could be slowing it down, but if that were the 
case, you'd think that the CPU load on the server would be much higher.

There is around about 2500-4000 contexts switches per second, im not 
sure if thats a high value or not.

Nathan Ward
System Administrator
Esphion ltd.