What linux lacks most - a decent remote fs

Cameron Simpson cs at zip.com.au
Thu Mar 27 00:22:22 UTC 2008


On 26Mar2008 15:45, Bob Kinney <bc98kinney at yahoo.com> wrote:
| --- Ian Chapman <packages at amiga-hardware.com> wrote:
| > Neal Becker wrote:
| > > I used unix/linux for many years.  In the past we've used nfs.  But nfsv3
| > > has no (useful) authentication.  Anyone can setup a rogue machine and
| > > pretend to be any uid/gid.
| > 
| > What I'd like to see is a way to forcibly unmount broken hard NFS 
| > mounts. umount -f seems to do squat.
| 
| I thought that hard NFS mounts were a thing of the past--like the mid '90s.

Not if you want reliable batch behaviour in the face of NFS server
downtime. My previous workplace routinely ran jobs that took weeks.
With a hard mount the job just stalls until the server's back, then
continues. Which means you can do maintenance that requires downtime.

"hard,intr" is the common flag pair, allowing you to at least interrupt
a stalled IO to a down server, getting your job back.

| Isn't it preferred to set them up with an automounter to prevent panic
| when communication falters?
| I've looked into it a little bit, and it seems like it can be done, but for
| the frequency that I use NFS, I took the quick-and-dirty route.

Autofs isn't enough. If you run it with a smallish idle timeout (to
umount when a remote fs is unused long enough) it reduces your exposure
to down servers, particularly handy when you want to reboot a client,
but also handy for those processes that walk the mount table to find
stuff out - avoiding a stall on a down mount mountpoint.

However, it only reduces the problem. There's no magic in autofs, and a
stalled mount point is still a stalled mount point. And of course autofs
introduces its own collection of issues (mostly rare and minor).

Regarding CIFS, yes it sucks. No symlinks, case issues etc. All from
trying to do sensible work through the rather braindead collections of
arbitrary incapabilities that M$ foist on their users.

NFS has its troubles, but it's a much closer semblance of a UNIX
filesystem than CIFS will ever be.

I run Samba/CIFS at home _purely_ to present a hard drive to our CIFS-only
PVR. The Neuros OSD speaks NFS nicely, and NFS is what I use with it.

Cheers,
-- 
Cameron Simpson <cs at zip.com.au> DoD#743
http://www.cskk.ezoshosting.com/cs/

Trust the computer industry to shorten Year 2000 to Y2K. It was this
thinking that caused the problem in the first place.
- Mark Ovens <marko at uk.radan.com>




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