SUMMARY : Using NFS

From: Marcello Frutig (frutig@inf.puc-rio.br)
Date: Wed Mar 25 1992 - 16:25:57 CST


Here is my original question :

>
> Dear sun-managers,
>
> We have here three IP subnets connected via 2 PCs running KA9Q-router.
> The problem is how to mount file systems with NFS between the SUNs that
> belong to different subnets. In the case of a failure in one of the routers,
> we don't want to see the SUNs going down because the server is unreachable.
> Here is the situation :
>
>
> -----------------------PC--------------------PC--------------
> | | |
> Sun #1 Sun #2 Sun #3
> home FS Mail Server home FS
> application FS application FS
> mount home from Sun #3 mount home from #1
> mount app from Sun #3 mount app from #1
> mount mail from #2 mount mail from #2
>
> Following the manual, I should mount "read/write" FS with HARD/INTR options.
> But, even with INTR, aborting the request is being impossible.
>
> Systems : SUN OS 4.1.1b and 4.0.3.
>
> I would appreciate any kind of help. Thanks in advance,
>
>
> Marcello Frutig E-Mail : frutig@rdc.puc-rio.br
> PUC-Rio, Rio Datacentro Fone : 021 529 9422
>

The solution is use the automount (SUN OS) or a freeware program called "amd".
These programs let you mount/umount file systems based on demand.

Thanks to

David Fetrow <fetrow@orac.biostat.washington.edu>
sg@geoquest.com (Sridhar Gantimahapatruni)
Perry_Hutchison.Portland@xerox.com

and special thanks to

atwell@cadre.af.mil (Capt Bart Atwell)

Capt Bart send me a complete example of using automount. Please let me know
if you are interested and I send you a detailed summary.

M. Frutig.

-------------------------------------------------------------------------------
From: atwell@cadre.af.mil (Capt Bart Atwell)
Hi,

We use the automounter for this situation. It permits mounts that don't
hang because if the server of a file system goes down, the automounter
will time out and the mount will be disconnected. The System and Network
Admin. manual describes the automounter fairly well but if you can't
figure it out, write back and I can help more.

Good Luck

Bart
-------------------------------------------------------------------------------
From: David Fetrow <fetrow@orac.biostat.washington.edu>
 NFS is kind of ugly about this kind of thing. The workaround is to use
automounter (or the 3rd party "amd", freeware). This mounts the filesystems
only when they are needed and dismountes them after they haven't been
used after say....5 minutes or so.

 It was a bit of a pain to set up but if one or the other machine is
unreachable more than a few minutes/week it's worth the effort. Don't
try it without the manual or someone who has done it before though;
there are some REALLY counterintuitive things in there.

-- 
 -dave					   fetrow@biostat.washington.edu
-------------------------------------------------------------------------------
From: sg@geoquest.com (Sridhar Gantimahapatruni)
You can automount the file systems. For example, Sun #1 can automount stuff
from Sun#2 and Sun#3 and vice-versa. Automount mounts the file systems as they
are accessed and umounts them after they are not accessed for a specified
period of time. Chapter 15. in Sun System And Network Admin. Manual provides
the details for setting up automount. 

Hope this helps.

sridhar ganti. ganti@geoquest.com -------------------------------------------------------------------------------



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