Instance terminated by VKTM

You  could see errors like the following :



ORA-00445: background process "ARC2" did not start after 120 seconds
Wed Apr 04 04:59:39 2012
Incident details in:

Wed Apr 04 05:02:33 2012
VKTM (ospid: 5604): terminating the instance due to error 1092
Wed Apr 04 05:02:40 2012
System state dump requested by (instance=1, osid=5641 (LGWR)), summary=[abnormal instance termination].
System State dumped to trace file
Instance terminated by VKTM



PMON (ospid: 11508): terminating the instance due to error 471
Wed Apr 04 12:04:31 2012
System state dump requested by (instance=1, osid=11530 (DIAG)), summary=[abnormal instance termination].
System State dumped to trace file
Dumping diagnostic data in directory=[cdmp_20120404120431], requested by (instance=1, osid=11530 (DIAG)), summary=[abnormal instance termination].
Wed Apr 04 12:04:35 2012
Instance terminated by PMON, pid = 11508


Solution : check ntp server and the date on your server