re: Are NFS handles stable across major updates?

[matthew green <mrg%eterna23.net@localhost>]

Edgar Fu? writes:
> When I take down an NFS server, update the base system (say, from -6 to -8), 
> and bring it up again, will clients that have NFS handles open across the 
> downtime/update access the same files (under the assumption that I mount 
> everything to the same place after the update) under their handles?
>
> In other words: is the NFS handle to VFS whatever stable across NetBSD 
> versions?

in my experience, yes, but there's a pretty serious caveat:  if you're
NFS exporting dk backed file systems, then it's possible for any reboot
(upgrade or not) to re-number the dks found and thus break the existing
mounts (will return stale handle now.)

basically, anything that changes the device number of the underlying
file system will break NFS during reboot (eg, wd1e becoming wd0e when
wd0 fail is another case.)  hard-coded real devices, raidframe without
dk, these can be made to be stable.. the rest is annoying.

one suggestion is to have a mount option to supply this id info so
it can remain stable, but no one has implemented it yet.


.mrg.