NFS server fail-over - how do you do it?

[Chuck Swiger]

adp wrote:
> One of my big problems right now is that if our primary NFS server goes down
> then everything using that NFS mount locks up. If I change to the mounted
> filesystem on the client then it stalls:
> 
> # pwd
> /root
> # cd /nfs-mount-dir
> [locks]
> 
> If I try to reboot the reboot fails as well since FreeBSD can't unmount the
> filesystem!?

Solaris provides mechanisms for NFS-failover for read-only NFS shares, but 
FreeBSD doesn't seem to support that.  Besides, most people seem to want to 
use read/write filesystems, which makes the former solution not very useful to 
most people's requirements.

The solution to the problem is to make very certain that your primary NFS 
server does not go down, ever, period.  Reasonable people who identify a 
mission-critical system such as a primary NFS server ought to be willing to 
spend money to get really good hardware, have a UPS, and so forth to facility 
the goal of 100% uptime.  A Sun E450 still makes a nice primary fileserver, 
although NAS solutions like a NetApp or an Auspex (not cheap!) should also be 
considered.

The other choice would be to switch from using NFS to using a distributed 
filesystem which implements fileserver redundancy, such as AFS and it's 
successor, DFS.

-- 
-Chuck