Coda File System

Usage problems.

From: Grzegorz Nowakowski <>
Date: Mon, 16 Feb 2009 21:17:25 +0100
Hi Coda-ers  ;)

I'm new to Coda and to this mailing list so hi again.  That said, I've
looked at your project for long time, just couldn't find any to actually
try and use it.  Now I've recently deployed small installation in my
home network and got some problems/questions I hope you can help me to

Mind you, I did RTFM (in fact, I did it long before I ever touched Coda
itself).  So If something is explained somewhere, just remind me where
it is and I will find it.

For reference, the server is based on Atom 1,6GHz with assigned 256MB of
RAM, client is Athlon 2400+ with 1GB of RAM.  There is root volume and
there is /home/$user volume, and only the latter is used for data
storage now.

1. What is practical maximum volume size, in terms of used space and
number of files?

2. What is practical maximum file size to be pushed around?

Use case: I have already learned that Coda isn't good choice for filer
with size of hundred gigabytes.  I have settled for my /home/$user.  It's
about 1,5GB and has about 30k files.  Yet even with this amount of data
venus tends to eat more than 80% CPU, clog the system and become totally
unrensponsive.  Restarting daemon helps for a while but the problem
returns in few hours, even if Coda filesystem is not touched in the
meanwhile (unless running vcodacon counts).

3. Is it possible to manually force volume hoarding and synchronisation?
Preferred is some blocking operation, so that there is known exact
moment when work is finished.  Observing vcodacon helps of course but I
found it a bit unreliable.

4. Is it possible to verify cache contents?  That is, to determine
whether given file/directory is viewed remotely or is taken from local

Use case: I mix laptop to the game.  Despite issuing 'hoard add .
100:d+' at the top level of home volume (and keeping it connected for
few hours), after taking laptop somewhere else I have discovered that the
replica was incomplete.  A bit annoying, considering that missing were
the very files I intended to work on.  What I miss is manual control
over local cache, so I could force and verify synchronisation.

Also, I haven't got success with opposite operation: purging cache (to
save some filesystem space).

5. How can I instruct venus to forget realms?

There are some leftovers from my earlier attempts.  They are quite
defunct now so there is no need to be reminded about them.

>From here on there are no actual problems.  More like random ideas.

6. Have you considered streaming?

My current understanding is that if I want to access file it is wholly
copied to the cache in the first place.  Which is a bit troublesome when
trying to access big files in this way.  Movies for example.  In which
case it would be perfectly acceptable to start serving user partial
file, before it's fully downloaded.

7. Is it possible to set per-volume quota?  Like the hard limit on
volume size?  AFAIK there is only per-user quota which sometimes is not

8. The user programs are confusing.  Maybe it would be good idea
to supply common frontend to them?  Like VCS programs do.

In general, I have mixed feelings.  I really like Coda and despite
problems I have, I'm very far from saying it sucks.  It's really good
piece of work which I'm sure I couldn't do better in reasonable time.
Yet the problems are annoying and I can't even use alternative because
there doesn't exist any!  I haven't found another remote filesystem with
persistent local cache, with the ability to work disconnected.  So I
just can't help quoting Duke Nuk'em: "this really pisses me off".  :)

Once again, please accept my appreciation of your good work and I hope
it will get even better.  Cheers,
Grzegorz Nowakowski
Received on 2009-02-16 15:49:51