Coda File System

Re: Is Coda Right For Me.

From: Ivan Popov <>
Date: Tue, 15 Oct 2002 20:24:23 +0200 (MET DST)
Hello Kevin,

to avoid going into all details I am trying to find the critical one(s):
I am a bit afraid you expect NFS- or SMBFS-like behaviour from Coda
concerning latency.

On Tue, 15 Oct 2002, Kevin Atkinson wrote:

> machine.  Then copy the files which vary anywhere from (100 - 2000 MB)

> Consistent read and write throughput is also important, especially
> when capturing video.  I expect read throughput to be consistent for
> reading large files which are not yet in the cache so the playback
> will be smooth.

The throughput on an open file is exactly that of the local filesystem -
because the file *is* local, in the cache.

But a close() after writing and open() before reading will be very
time-consuming. I haven't tried Coda on 100Mbit network but I can't
expect over 7Mbyte/sec anyway, so when you start a playback of a 2000M
file from Coda, you will have to wait 5 minutes at least (the first time).
Similarly with ending a recording.
(btw if you have replicated servers, the close() time will grow
proportionally to replication count - as multicasting is not used
by current Coda)

And of course you will have to have lots of cache space.

Another note - I am unsure what do you mean with "backup", Coda might be
right or wrong depending on your expectations. Replication is not really
backup :)

Otherwise at first glance your plans seem doable!
(don't think anybody ever tried to share the client cache - and
corresponding metadata - between two OSs)

Received on 2002-10-15 14:25:57