[OpenAFS] Re: WAN speed

[Andrew Deason]

On Fri, 23 Mar 2012 01:02:10 +0200 (EET)
jukka.tuominen@finndesign.fi wrote:

> > 109M single file:
> >
> > SSH to AFS ~525KB/s
> > AFS to SSH ~800KB/s
[...]
> I tried turning off encryption, but it didn't make a notable
> difference with either file transfer test

Okay, well that's obviously better but still much lower than the
theoretical. There are a few more switches you can fiddle with:

 - increase the chunksize by passing -chunksize to afsd (you have to
   restart the client to change this). Try '-chunksize 20' for 1M, or
   '-chunksize 23' for 8M, or something around there.
 
 - try memcache instead of disk cache (I assume you're using disk
   cache). Do this by passing -memcache to afsd, but this will use RAM
   instead of local disk for the caching stuff, so you might need to
   lower the cache size in 'cacheinfo'.
 
 - try 'cache bypass' (with disk cache) which you can turn on with 'fs
   bypassthresh'. But keep in mind cache bypass is still a new feature
   and may not be entirely stable.

If it still seems slow no matter what you try, what may be helpful is if
you can provide the output of:

rxdebug <client> 7001 -rxstat -noconn
rxdebug <server> 7000 -rxstat -noconn

So we could see the rate of resends and such for Rx. Provide that output
both immediately before and immediately after you try a transfer.

You can also try a benchmark using 'rxperf' to see how fast rx itself
goes, which could help rule out what the bottleneck is during the
transfer. If you want to try that but are not sure how to use it, let us
know.

-- 
Andrew Deason
adeason@sinenomine.net