SAP Note 25619 - ISHCM problems with NFS mounted disk drives

Symptom:

The R/3 communication module works if it writes on a local disk drive. However, as soon as a disk drive is mounted via NFS, then the R/3 communication module no longer works.
The HCM programs remain hanging since the transceiver programs themselves are also hanging.

Cause and prerequisites

This problem is caused by locking problems.

Solution

Eliminate the locking problems. The following situations can cause this problem:

1. Another application has set a lock on the file or on SS_STAT.dat.

2. the authorizations for the file or for SS_STAT.dat are incorrect. They should be set to 0666 (rwrwrw in UNIX).

3. Program PUT_TAB is unable to create the file in this directory. Possibly, also to change authorizations.

4. NFS-specific mounts should be checked whether the NFS processes LOCKD and STATD are running correctly in both systems. On the NOVELL side, you must ensure that the file locking mechanisms are to be used when mounting. These are absolutely necessary.
If hanging situations have already occurred, the hanging UNIX processes canot be exited using KILL -9. This is an indication that the processes are hanging in the operating system kernel. The only way out here is to restart the system.
On HP platforms there was (possibly still is?) in this context a bug: the lock entries of other computers were not removed in the directory /etc/sm (or /var/statmon/sm or similar). To be on the safe side, this directory should therefore be emptied before you restart the system.

Additional key words

Communications module, RNCSND01, RNCGET01, RNCGET02, RNCGET03, transceiver, PUT_TAB, GET_TAB, SS_STAT, SS_STAT.dat, consulting