If the pfs_qualifier field displayed in the MOUNT
LATCH ACTIVITY or FILE SYSTEM LATCH ACTIVITY table
shows either Running or Osi Wait,
do the following steps depending on the type of file system in question:
For a zFS file system, do the following (see
z/OS Distributed File Service zFS Administration for
more information):
- Issue the DISPLAY ZFS,QUERY,THREADS to get details
about the state of threads within zFS.
- Issue modify zfs,hangbreak to have zFS to post
any requests in zFS that are waiting, with a failure. This can allow
the hang condition to be broken and resolved.
- Issue the modify zfs,query,threads command to
determine if one or more requester threads remain in the same wait
over several queries.
- If you cannot successfully break or resolve the hang, go to Terminate or cancel the latch holder
For an NFS client, most problems relate to the socket sessions
that NFS has with its servers. Do the following:
- Issue the DISPLAY OMVS,FILE command to show the
MOUNT PARM= value specified when the file system was mounted. This
value contains the name of the remote server and the remote directory
path name for the file system where the file is.
- Find out whether the delay is in the remove server or the NFS
client. To find out, issue the DISPLAY TCPIP,,NETSTAT,CONN command
to display the state of the socket sessions between NFS and the remote
server (which is always port number 2049). If the output shows that
there are no socket sessions between the NFS client and the remote
server, either the remote system or the remote server might be down.
However, note that NFS does not always have persistent socket sessions
for its servers, so the absence of sessions may just mean that socket
sessions are not needed at this exact time.
If the remote system
or server is down and the file system was hard mounted, NFS will try
to establish contact indefinitely. In that case, you might have to
unmount the file system to free up the users.
You can also
use the shell ping command to check for connectivity to the remote
system. Use display commands on to the remote server's system to
see why the server is not responding. If the remote system is also
a z/OS® system, you can diagnose
the latch contention on the remote system starting with step 1.
For the DFS Glue
module, IOEGLUE, the wait usually means that the file system is
exported by the SMB or DFS server and that the file being accessed
is being shared with some remote client. Issue the DISPLAY
OMVS,A=ALL command to display the SERVER= line that can help
to find the address space and process id of the server involved. See z/OS Distributed File Service SMB Administration for
diagnosing SMB problems like hangs.
If you can not free the latch holder with these methods, you might
need to force the process to terminate, or cancel the latch holder.
See Terminate or cancel the latch holder for more instructions.