Luke Schwab wrote: > In migrating from **VM to ZFS am I going to have an issue with Major/Minor > numbers with NFS mounts? Take the following scenario. > > 1. NFS clients are connected to an active NFS server that has SAN shared > storage between the active and standby nodes in a cluster. > 2. The NFS clients are using the major/minor numbers on the active node in > the cluster to communicate to the NFS active server. > 3. The active node fails over to the secondary node in the cluster. > 4. The NFS clients can no longer access the same major minor number for NFS > shares. > > Does anyone know how ZFS fixes this problem. I read something on NFSv4 in > Linux that has the "fsid" option of mount that allows you to set the device > name instead of the major/minor number. Does Solaris 10 have anything like > this?
Hi Luke, The NFS clients (any version) need a stable "filehandle" to be given out and consistently recognized by the server. Proper clustering solutions generate a filehandle based on the filesystem data in the underlying shared storage (not just the accidental major and minor numbers the server filesystem uses to access the storage), and also put critical state in the shared storage, and so when the standby node takes over, it can find the same files by the clients' filehandles and assure service continuity. An upcoming version of SunCluster will support ZFS this way, but ZFS won't do all that is necessary by itself. The exception to this is that NFSv4 defines a way to do a "migration" to another server; this is best for planned changes, as the original server should appear to be alive enough to hand back a pointer to the new location. Solaris doesn't currently have support for migration at all; when we get to it, we'll be working on the client side first. Rob T
