Solaris redundant nfs mounts

Stardate 90840.8 Nfs servers with lots of disks, sharing files out to multiple clients, is a pattern followed everywhere. Eventually your users begin to not only use these remote files, but start to put nfs directories into their PATH variable. This causes problems whenever you need to patch or reboot the nfs server because all shells launched by users with PATHs that look into the nfs directories will hang forever(this does assume you are mounting hard).

You can minimize the effect of this by using redundant mount information.

Before:

/usr/local -ro,hard,intr,suid  bunny.cat.pdx.edu:/disk/forest/local

After:

/usr/local -ro,hard,intr,suid  bunny.cat.pdx.edu:/disk/forest/local,caerbannog.cat.pdx.edu:/volumes/cave/misc/usr-local

It is best to maintain an idea of a primary and secondary, at least for administration. Modify only the primary, and rsync to the secondary. Use readonly mounting to mount. This mount appears in ``mount`` like this:

/usr/local on caerbannog.cat.pdx.edu:/volumes/cave/misc/usr-local,bunny.cat.pdx.edu:/disk/forest/local remote/read only/setuid/devices/rstchown/hard/intr/xattr/dev=5a0000e on Wed Mar 27 15:35:21 2013

Note that this is mounted on both servers. Packets get sent to both servers and the first to respond with valid information is reported to the system. This can make for some bizarre weirdness if you use readwrite mounts.

It is totally possible to use something like drbd between nfs servers (not on Solaris, obviously), to make this doable with readwrite mounts. I have not done this personally.