Investigation of offline NFSv4 caching in Ubuntu Lucid (conclusion: not yet)

Our users mount their home directories over NFSv4. We wonder if they can have an offline cache, so they may continue using their home directories while offline, and the FS takes care of resyncing when their PC comes online again.

NFS itself has client side caching, both read and write (see “DATA AND METADATA COHERENCE” and “NFS version 4 caching features” in the NFS manpage. This is not meant for offline use.

For Linux, there exists FS-Cache, with at least CacheFS and Cache-files as backends, which should be usable to provide an offline cache for NFS. But the initiative needs to come from the NFS to be cached, not from the user, and NFS isn't taking the initiative on Lucid, yet.

Some other distros offer ways to cache an existing NFS mount using CacheFS though. And the cachefiles daemon is available in Ubuntu.

So I guess just waiting a little longer will bring a solution.