Messages in this thread | | | Subject | Re: How to manage shared persistent local caching (FS-Cache) with NFS? | From | Jon Masters <> | Date | Wed, 05 Dec 2007 12:49:59 -0500 |
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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.
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