We have an ongoing issue with our automounter freezing and refusing to 
mount more nfs shares.

When it enters this state it blocks any calls to the mount point it is 
trying to mount but existing mount points are accessible.

We've been unable to discern a pattern and we have to kill and restart 
the autofs service each time the problem occurs.

Our automounter maps are help in a LDAP.
Our nsswitch.conf file has:

snip---
automount:      ldap
snip---

And this is a snipit of the relevant sections of our LDAP along with an 
example of how my home dir mapping is stored.

snip---

# auto.master, geos.ed.ac.uk
dn: nisMapName=auto.master,dc=geos,dc=ed,dc=ac,dc=uk
objectClass: top
objectClass: nisMap
nisMapName: auto.master

# /home, auto.master, geos.ed.ac.uk
dn: cn=/home,nisMapName=auto.master,dc=geos,dc=ed,dc=ac,dc=uk
objectClass: nisObject
cn: /home
nisMapName: auto.master
nisMapEntry: ldap:nisMapName=auto.home,dc=geos,dc=ed,dc=ac,dc=uk

# fgibbins, auto.home, geos.ed.ac.uk
dn: cn=fgibbins,nisMapName=auto.home,dc=geos,dc=ed,dc=ac,dc=uk
objectClass: nisObject
cn: fgibbins
nisMapName: auto.home
nisMapEntry: home10.geos.ed.ac.uk:/disk/home/u10:glg/&

snip---

A quick google indicates this is not a common problem and, frankly, I'm 
stumped. I've trawled the RedHat bugzilla and have seen nothing apt.

Apart from setting up a system with automounter running under strace 
with a client hitting it I'm not sure where to go with this problem 
(attaching strace to a frozen autofs has not helped).

If you've encountered autofs behaving this way please let me know.
If you know what is causing the problem please let me know ++ and if you 
have a handle on fixing it please let me know (++)++.

Faye

PS. Our LDAP setup used multiple redundant servers and there is no 
correlation with any LDAP downtime. Also our quotaing system, UID lookup 
(also LDAP) and DNS resolution are ruled out as culprits as failures 
there would affect other parts of the system. All our servers use ntpd.

PPS We had this problem on SL5.0 (we moved from 5.0 straight to 5.3). 
The persistence of this issue after our migration prompted this call for 
help.

-- 

---------------------------------------------------------
Faye Gibbins, Computing Officer (Infrastructure Services)
      GeoS KB; Linux, Unix, Security and Networks.
Beekeeper  - The Apiary Project, KB -   www.bees.ed.ac.uk
---------------------------------------------------------

   I grabbed at spannungsbogen before I knew I wanted it.
                  (x(x_(X_x(O_o)x_x)_X)x)

The University of Edinburgh is a charitable body,
registered in Scotland, with registration number SC005336.