This post explains about forcing a system crash dump when the system is in a hang condition and crashdump files are required for Oracle root cause analysis.In most cases, a system crash dump of a hung system can be forced. But this won;t work in all type of system hang conditions. In order to force crash dump,you need to send break signal from console and bring the system to OK prompt and suspending all current program execution.
If the system is not able to ssh/telnet and not able access via console,then you need follow the below method to force the system to crashdump.
Login to server console ,
After sending break signal ,system will be able to to drop to OBP(OK prompt).Its again break command may vary depends on sun server model.This procedue will work on v-series servers where you will get sc promt.
Type ‘go’ to resume
If you don’t see this message, you were probably not successful in stopping the system.Once at the ok prompt, type sync and press Enter.
The system will immediately panic and hang condition has been converted into a panic, so an image of memory will be stored in /var/crash/ location depends on dumpadm configuration. After saving the dump,system will attempts to reboot.