I talked with a few filesystem experts within Red Hat. They said...
- ext3 has a limit of 4KB for xattr data. If you use the standard encoding of
8 bytes per uid, that has a limit of roughly 100 entities that could be
associated with a file. Is this too limiting? I dunno. Perhaps it need not
be too limiting if more extensive use of group-based-ACL's are used.
- XFS could possibly allow a maximum of 64KB xattr's per file, but that is
very inefficient in filesystem storage.
- xattr's are currently not supported by NFS.
The other thing to concider is backup and restore of acls and xattrs. I think
this area is probably a weak spot as well but I believe star and rsync do
have some kind of support for acls.
--
Matthew Galgoci
GIS Production Operations
Red Hat, Inc
919.754.3700 x44155