[CentOS] FSID and NFS

[Filipe Brandenburger]

On Sat, Aug 16, 2008 at 11:30, Mag Gam <magawake at gmail.com> wrote:
> What is the purpose of FSIDs? I am exporting 30 volumes via NFS. Do I
> need a FSID option?

FSID is needed in NFSv3 if the devices you are exporting may change
minor numbers across reboots. For example, if you have a filesystem on
/dev/sdc1 that you mount and export, if it is always /dev/sdc1 (and
not sometimes /dev/sdd1 depending of having another disk attached
during boot time) you don't need it. However, if you are exporting
filesystems which are mounted on LVM volumes (which will change order
on the next reboot if you create or destroy new logical volumes) you
should set FSIDs explicitly to avoid them changing on the reboot.

If you don't set the FSIDs explicitly, after a reboot of the NFS
server, you may experience NFS clients that show the contents of a
different filesystem where you formerly had a specific one mounted, or
more frequently you will have your mounted filesystems with "Stale NFS
filehandle" errors. You will have to unmount and remount the
filesystems on all clients to fix these problems.

HTH,
Filipe