From: mwills@su102c.ess.harris.com (Scott Wills)
Subject: Re: automounter - help needed in hierarchial mount situation
Date: Tue, 29 Sep 1992 14:25:03 GMT
Distribution: usa
Reply-To: mwills@x102a.ess.harris.com (M. Scott Wills)
Organization: Harris Corporation, Government Aerospace Systems Division.

mdpc@crash.cts.com (Mike Parker) writes:

>Ok, on the server system, there are two different EXPORTED partitions:

>	/toplevel
>	/toplevel/build/other

>I am having difficulties on the client machines in getting the automounter
>to mount this type of structure.  The message I get on the system log is
>something to the effect of "heirarchial mount".  The use of /toplevel
>on the clients seems to work, but /toplevel/build/other is not mounted at
>all.

I've run into the same problem here.  I don't think you can do it from
a the Sun automount daemon.  Quoting automount(8):

     Mount points for a single automounter must not be hierarchi-
     cally  related.  automount will not allow an automount mount
     point to be created within an automounted filesystem.

The first sentence seems to imply that a second automount deamon could
do it, but the second sentence rules that out.  A recent question
asking if AMD can handle heirarchial mounts went unanswered.
Experienced AMD'ers, please comment.  The big advantage of AMD appears
to be in graceful handling of unresponsive NFS servers.  It makes
every effort not to block, while Sun's automount blocks at the drop of
a hat.

Please chime in with useful info on your site's use of direct
and indirect maps.  AMD offers more types of maps, but I can't seem to
duplicate the functionality we had with automount.  In addition to the
/home/someplace mounts, we have most of /usr installed on each
machine.  Then some of the larger stuff (X11R5, openwin fonts, etc).
are mounted from other places.  To do this we had a direct map like:

/usr/nn			-ro,soft	foo:&
/usr/docs		-ro,nosuid,soft	bar:&
/usr/frame3.0x		-ro,nosuid,soft	bar:/someplace/frame3.0x \
					yuiop:/anotherplace/frame3.0X 
/usr/openwin/lib/fonts	-ro,nosuid,soft	bar:& foo:&
/cdrom			-ro,nosuid,soft	bar:&
/usr/local/bin		-ro,soft,	qwert:&
/usr/local/lib		-ro,nosuid,soft	qwert:&
/usr/local/man		-ro,nosuid,soft	qwert:&
/usr/local/demo		-ro,nosuid,soft	qwert:&
/usr/X11R5		-ro,soft,	qwert:&

I know we could improve on the /usr/local stuff, making it a single
mount with an additional ":", but none of the /usr stuff works at all
for me on AMD, because specifying a mount point of /usr for the direct
map hides the local /usr partition.  The AMD docs hint that I could
mount /usr over in /a/localmachine/usr (or /tmp_mnt/localmachine/usr),
and let AMD find it there, but that seems inefficient.  Is that the
best/only way?

I might also mention that the timeo= and retrans= values seem to be
ignored by automount, which makes it pretty useless for distant
machines.

Scott
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