RMAN error ORA-00230: operation disallowed: snapshot control file enqueue unavailable

I found an error message in the alertlog about RMAN backup.

Mod Nov 07 08:46:02 NZDT 2011
Starting control autobackup
Autobackup failed with following error
ORA-00230: operation disallowed: snapshot control file enqueue unavailable

The error looks like other process is holding the controlfile hence the rman can’t do the snapshot. Most likely is the previous backup process job is still holding it, so let’s check what we have in the database

SQL> select sid, serial#, status, logon_time from v$session where program like ‘%rman%’;

SID SERIAL# STATUS LOGON_TIME
—– ——- ———— —————
198 67 ACTIVE 06-NOV-11
219 31393 INACTIVE 06-NOV-11
203 10571 INACTIVE 06-NOV-11
210 403 INACTIVE 06-NOV-11
199 3791 INACTIVE 06-NOV-11
200 2627 INACTIVE 06-NOV-11

as we can see there are left running processes over the weekend. Now the question is why the weekend backup process is still running? I checked the filesystem and found I can’t access (hung session) the autofs mount point, this is the reason why the process is still running. The SA restarted the autofs process to resolve the issue