Coda File System

Re: General Coda Questions

From: Ivan Popov <>
Date: Fri, 11 Feb 2005 17:53:28 +0100
Hello Jan,

On Fri, Feb 11, 2005 at 12:28:46AM -0500, Jan Harkes wrote:
>And since the defaults assume an average 16KB
> filesize, simply setting the venus cache size to something like 2GB
> would try to give you a monster client that probably won't even be able
> to start. So you also need to set the cachefiles= option in venus.conf
> to a more realistic value (5000 or 10000).

not questioning the sense of your remark, but just talking about
the possible size margins - I am running a client with 4GB cache
and it behaves nicely, no matter how full the cache is populated.
(it is used purely read-only though, so it does not exercise cache replacement
for locally updated objects).

Such cache size should give enough space to play with the biggest
possible file sizes (under 2G) - though I did not ever try anything
bigger than CD-images.

> The way Coda works is that we only get to see 'open' and 'close' and
> none of the read/write/mmap stuff that comes in the middle. So you
> really do need to have enough diskspace to store the whole thing in the
> local cache.

I think nowadays it is possibly the least important of all Coda limitations :)
as local disk for the cache is cheap.

> > a) Can coda work with really large files 1GB and up, without major problems ?
> Don't really know, there is definitely a 2GB ceiling, since we only use a
> 32-bit integer to represent file size in our RPC2 protocol.

Have you got a list of "incompatible, but necessary changes" for Coda?
It would be nice to have a view on the magnitude of the problems to solve,
if/when we break compatibility - or possibly introduce forward-compatibility
and later break backward one...

Best regards,
Received on 2005-02-11 11:55:20