[Beowulf] Storage and cachefs on nodes - NFS support exists

[hanzl at noel.feld.cvut.cz]

I have the pleasure to give you very optimistic update on persistent
file caching. Few days ago I wrote these skeptic lines:

> I am not sure how much can I expect from linux cachefs as seen in
> e.g. 2.6.9-rc3-mm3 - if I got it right, it is a kernel subsystem with
> intra-kernel API, being now tested with AFS and intended as usable for
> NFS. It is however "low" on NFS team priority list. So linux cachefs
> might provide cleaner solutions than Solaris cachefs - if it ever
> provides them.

and now	I see that NFS already can use this local-disk-caching subsystem!

There is linux-cachefs maillist for this, you may want to read:

http://www.redhat.com/archives/linux-cachefs/2004-October/msg00027.html
- 2.6.9-rc4-mm1 patch that will enable NFS (even NFS4) to do
persistent file caching on the local harddisk

http://www.redhat.com/archives/linux-cachefs/2004-October/msg00004.html
- older message explaining what is going on

http://www.redhat.com/archives/linux-cachefs/2004-October/msg00019.html
- about ways to get this to the mainline kernel

http://www.redhat.com/mailman/listinfo/linux-cachefs
- list archives and subscription page


I believe that this subsystem will be an immense help for work on huge
data with mostly read access.

And much less administrative hassle - once this gets to the mainline
kernel (well, yeah, any help to push it there is welcome!) it will be
much much easier to use. Just a normal NFS server. Just a normal NFS
client with the NFS_MOUNT_FSCACHE or NFS4_MOUNT_FSCACHE mounting
option ON.

Hope that this attempt to make relatively simple persistent caching
for Linux will catch up and survive even kernel_version+=0.2 (usual
killer for similar projects).

Best Regards

Vaclav Hanzl