[OpenAFS] UDP slowness remedies?

Steve Simmons scs@umich.edu
Mon, 25 Oct 2010 16:35:39 -0400

On Oct 22, 2010, at 2:44 PM, Dan Pritts wrote:

> Others will have to chime in on tuning the server for vos move.  I =
have one thought that might or might not help - do something like this =
from a host at source site.  I am far from sure of the syntax but you =
get the idea:
> vos dump srv part vol | ssh host-at-target-site vos restore srv part =

A couple of years ago we did some performance testing on different ssh =
encryption algorithms for bulk transfer to a single host. Forcing use of =
blowfish gave us the fastest throughput. This was at least partially a =
CPU issue; there were upwards of 10 machines dumping data via ssh to a =
single host with the equiv of 'tar cf - ... | ssh -c blowfish hostname =
tar xpf - -C /dirname'. That's close enough to Dan's suggestion that I'd =
expect blowfish to be a win for you.

Assuming you don't mind the data being viewed in-transit, get the =
Pittsburgh Supercomputer ssh version. It has switches that allow you to =
encrypt the authentication steps but sends the data in plaintext. If you =
do lots of simultaneous instances, CPU is drastically reduced or removed =
as bottleneck.

If you have enough CPU available, doing simultaneous instances of

  vos dump srv part vol | gzip | ssh remotehost 'gunzip | vos restore =
remotesrv ...'

is also your friend. Exact syntax of gzip/gunzip/ssh remote command left =
as exercise for the student. Note also that remotehost and remotesrv =
don't have to be the same.

Experimentation is your friend.