NFS Services Administrator's Guide (B.11.31.03) August 2008

has been sent to the NFS server and acknowledged. The O_SYNC flag degrades
write performance for applications that use it.
□ If multiple NFS users are writing to the same file, add the lockf() call to your
applications to lock the file so that only one user may modify it at a time.
If multiple users on different NFS clients are writing to the file, you must also turn
off attribute caching on those clients by mounting the file with the noac mount
option. Turning off attribute caching degrades NFS performance.
For more information, see mount(1M), open(2),write(2), and lockf(2).
“Too Many Levels of Remote in Path” Message
This message indicates that you are attempting to mount a directory from a server that
has NFS-mounted the directory from another server. You cannot “chain” your NFS
mounts this way. You must mount the directory from the server that has mounted its
directory on a local disk.
Common Problems while using Secure NFS with Kerberos
“Permission Denied” Message
This message could be displayed because of one of the following reasons:
• The Ticket Granting Ticket (TGT) has expired
To renew the ticket, enter the following command:
kinit username
• Fully qualified hostname resolution problem
To verify the hostname resolution, check the following files:
— /etc/nsswitch.conf
— /etc/hosts
To provide a fully qualified host name, do the following:
— Add dns in the host entry in the /etc/nsswitch.conf
— Re-configure NIS and /etc/hosts
• Time mismatch of 5 minutes between Kerberos server and Kerberos client
HP recommends that you run time server to synchronize the time between client
and server.
• Improper krb5.conf
This could be because the realm to domain matching is not set in either server or
client’s configuration file (krb5.conf).
To fix the krb5.conf file for proper domain name to realm matching, modify the
file based on the following sample:
136 Troubleshooting NFS Services