add info regarding fscache

docs/admin-guide/configuration/files/mount.md

@@ -75,7 +75,11 @@ nfs_idmap::domain: 'ethz.ch'
 Checkout [Permanent Kerberos with gssproxy and Password Keytab](../basic/gssproxy_with_keytab) if you want to access a Kerberos protected share, e.g. with background processes without having to type passwords (`kinit`) regularly.
 
 ### Caching
-NFS filesystem access can be speed up via local caching. This can easily done by specifying the mount option __fsc__.
+NFS filesystem access can be speed up via local caching. This can easily done by specifying the mount option __fsc__. 
+
+!!! warning
+    Due to a bug in the NFS client the `fsc` option need to be amended with the `nosharecache` option as well.
+
 If this option is specified Puppet will take care of the installation of the needed cachefilesd daemon and its configuration before doing the mount.
 
 Example:
@@ -84,7 +88,7 @@ mounter::def::modules:
   ensure: 'mounted'
   mountpoint: '/modules'
   device: 'lx-fs.psi.ch:/modules'
-  options: 'fsc,sec=krb5'
+  options: 'fsc,nosharecache,sec=krb5'
   type: 'nfs4'
 
 mounter::mounts:

docs/admin-guide/configuration/software/pmodules.md

@@ -52,7 +52,7 @@ mounter::def::pmodules:
   ensure: 'mounted'
   mountpoint: '/opt/psi'
   device: 'whatever-server.psi.ch:/pmodules'
-  options: 'fsc,sec=krb5'
+  options: 'fsc,nosharecache,sec=krb5'
   type: 'nfs4'
 
 mounter::mounts: