From: Jon Masters <jonathan@jonmasters.org>
To: David Howells <dhowells@redhat.com>
Cc: Peter Staubach <staubach@redhat.com>,
Trond Myklebust <trond.myklebust@fys.uio.no>,
Steve Dickson <SteveD@redhat.com>,
nfsv4@linux-nfs.org, linux-kernel@vger.kernel.org
Subject: Re: How to manage shared persistent local caching (FS-Cache) with NFS?
Date: Wed, 05 Dec 2007 12:49:59 -0500 [thread overview]
Message-ID: <1196876999.3325.5.camel@jcmlaptop> (raw)
In-Reply-To: <6306.1196874660@redhat.com>
On Wed, 2007-12-05 at 17:11 +0000, David Howells wrote:
> The downside of this is that each shared superblock only has one NFS connection
> to the server, and so only one set of connection parameters can be used.
> However, since persistent local caching is novel to Linux, I think that it is
> entirely reasonable to overrule the attempts to make mounts with different
> parameters if they are to be shared and cached.
I think the shared superblock approach is the right one, but I'm a
little concerned that there would now be different behavior for fscache
and non-cached setups. Not sure of any better idea though.
> The R/O mount flag can be dealt with by moving readonlyness into the vfsmount
> rather than having it a property of the superblock. The superblock would then
> be read-only only if all its vfsmounts are also read-only.
Given that, how many connection parameters are there that are likely to
actually differ on the same client, talking to the same server? Really?
> Would it be reasonable to have an outside way of setting directory options?
> For instance, if there was a table like this:
>
> FS SERVER VOLUME DIR OPTIONS
> ======= ======= ======= =============== =========================
> nfs home0 - /home/* fscache
> afs redhat data /data/* fscache
>
> This could then be loaded into the kernel as a set of rules which directory
> lookup by the filesystem involved could attempt to match and apply.
You could store the table in a NIS map, for example, and a udev rule or
similar could trigger to load it later.
Jon.
next prev parent reply other threads:[~2007-12-05 17:50 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-05 17:11 How to manage shared persistent local caching (FS-Cache) with NFS? David Howells
2007-12-05 17:49 ` Jon Masters [this message]
2007-12-05 18:03 ` David Howells
2007-12-05 19:54 ` Chuck Lever
2007-12-06 1:22 ` David Howells
2007-12-06 18:28 ` Chuck Lever
2007-12-06 20:00 ` David Howells
2007-12-07 17:59 ` Chuck Lever
2007-12-08 0:52 ` David Howells
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