[OpenAFS] About AFS performance over WAN

Giovanni Bracco bracco@frascati.enea.it
Thu, 27 Nov 2008 11:07:27 +0100

In our institution we have an AFS cell with clients and servers distributed 
over WAN. In the last year the bandwidth of the available WAN connections has 
been increased up to 1 Gbit/s for some of the sites and it appears that AFS 
performance over WAN is still limited to about 2-3 MB/s.

I know that this is a well know problem of the rx protocol, as shown for 
example by Hartmut Reuter at the last European AFS Conference 2008
(see slide 49 from 
due to the fixed rx window size and combined with network latencies in the 
order of tenths of milliseconds.

I am aware that an activity was in  progress for a tcp version of openafs, 
which probably could solve some of this problem, but  I do not know what is 
the status of this activity. 
More generally, what are the plans to increase the AFS performances over WAN, 
to take advantage of the present day availability of high bandwith 

Can someone comment about that?


Giovanni Bracco
(Servizio Informatica e Reti)
Via E. Fermi 45
I-00044 Frascati (Roma) Italy
phone 00-39-06-9400-5597
FAX   00-39-06-9400-5735
E-mail  bracco@frascati.enea.it
WWW http://www.afs.enea.it/bracco