Hi Buni and Hartmut,
thank you both for your explanations.
Binu, the explanation you gave regarding PxFS is along the lines of what I'd
expected.
Can we summarize the topic like this?
* To make fssnap work on PxFS ("global") mounts, several additional
requirements
regarding the PxFS layer and PxFS/UFS interoperation had to be fulfilled, so it
seems to be far from trivial to implement fssnap on PxFS.
* For non-PxFS ("HA-local") mounts, fssnap should work technically, even though
it is not supported. Care should be taken to minimize the impact of the
necessary I/O pauses during the snapshot process, for instance by temporarily
disabling cluster monitoring of resources depended upon the filesystem to be
snapshotted.
I'll see where I get from here.
Hartmut, regarding your comment:
> The problem is with the data and state of fssnap if a node should die
> during fssnap taking the snapshot.
Sure, UFS snapshots are temporary (see fssnap_ufs(1M)), but IIUC, snapshotting
an ha-local FS in a cluster should not be any different from snapshotting any
other (non-root) FS in that the (clustered or non clustered) node may die at
any
time, so the snapshot will get lost, right?
Again, thank you very much!
Nils
