Coda File System

Re: Coda over satellite link

From: Greg Troxel <>
Date: 29 Mar 2005 19:27:05 -0500
"Mark Colman" <> writes:

> Does anyone have any idea how well coda would work over a client-server
> link via satellite with a round trip latency of around 600ms and 384kbit
> bandwidth?

It should be reasonable; I use coda over a 28.8 kb/s modem which has
similar latency, or higher when loaded.  The read cache works well,
and I use 'cfs wd -age 30' to get write-behind caching.

> Does SFTP create sufficiently large windows to allow good utilization of
> the link?

I doubt it, since that's 28800 bytes in RTT*capacity.  I think it will
do 8 * 1k out of the box, but it should be possible to tweak the
constants up pretty easily.  SFTP/RPC2 really needs to be implemented
over TCP (separate connection for data, keeping a pool perhaps) or
SCTP - the transport protocol parts of it are a bit creaky.

Coda has some problems with very weak connectivity (remove files,
remove directory they were in before reintegrating rm of files used to
lose).  But I suspect you won't run into that too much if you stay
connected, or if you avoid 'rm -rf' while in write-disconnected mode.

        Greg Troxel <>
Received on 2005-03-29 19:27:48