Coda File System

Re: [ [PATCH] CacheFS - general filesystem cache]

From: Jan Harkes <>
Date: Tue, 31 Aug 2004 16:00:21 -0400
On Tue, Aug 31, 2004 at 02:02:40PM -0500, Troy Benjegerdes wrote:
> I noticed this on linux-kernel, and it looks very interesting... what
> does anyone think of the idea of trying to use cacheFS for the coda
> cache backing store? 

I am not sure about persistency across reboots. Also it assumes that the
cache is completely managed by some an in-kernel filesystem. So we would
need a lot of hooks and changes before venus can put anything in there.
It also makes its own decisions on when to purge objects from the cache,
probably not such a big problem. I don't know how it deals with writes,
it could very well be write-through only and assumes that anything in
the cache can be thrown out at any time without losing data.

It was probably designed for an NFS-like client that is completely in
the kernel and caches on a page granularity. The last time I checked
David Howells' AFS client was an NFS client that happened to use
AFS-compatible rpc calls to talk to the server. But that was a while ago
so I'm not sure if it has changed much since then.

In any case, I believe even if it is useful, we will still need our own
cache for the metadata and directories and probably for local mutations
that are waiting to be reintegrated. But on the other hand, it could rid
venus from the day-to-day cache-management details and let venus focus
on a smaller variable size cache that only deals with metadata and a
CML. And yes, without restructuring the linux and other platforms would
diverge considerable and make it a big pain to maintain.

Received on 2004-08-31 16:03:43