[Dovecot] I stream read - stale NFS file handle (reboot of server)

[Damon Atkins]

In the old days NFS Shared Path had a static handle (ie a number), 
normal based on some number pulled out of the file system/inode.
To fix (well work around) a security issue, for about 10+ years now, 
when a NFS server reboots, it generates a new random handle for the NFS 
Share. (sever may generate a new random handle per mount request)

The NFS Stale Handle happens when the client is still using the old NFS 
handle, the only fix is a remount

Some NFSv3 server let you fix the handle id for NFS share so it does not 
change over reboots. (this is how NFS clustering works, sometimes you 
need to install cluster software if the exportfs/share command does not 
let you hard code the fsid by hand.

The other option is to use NFSv4 which is design to handle reboots by 
servers.