Troubleshooting system-level problems

Saving the system dump memory image

If the system has panicked because of an unrecoverable failure, an image of system memory at the time of the panic may have been saved to a hard disk. By default, the partition used by the system to store the system memory image is also shared by the swap facility. Therefore, if you plan to examine the system memory image with crash, it must be saved before the system comes up. However, saving the system memory image is not required, and no system software will be damaged if you continue on to multi-user state.

NOTE: If a system dump is directed to a dump device other than the default swap device, the dump will not be detected when the system boots up. To enable the system to detect a dump that is not in the swap area when the system boots, add the following entry into the file /etc/dumptab:

   /dev/dump       0       -

When you try to reboot the system and there appears to be a system memory image saved, the following message is displayed automatically if the dump device is also a swap device:
```
   UX:dumpcheck: INFO:
   There is a system dump memory image in a swap device.
   Do you want to save it? (y/n)>
```
NOTE: The timeout value for the dump image prompt can be set using the defadm command as follows:

defadm dump TIME=secs
Answer y to save the system dump memory image. When you are given a selection list of what media to use for the dump, enter the appropriate value for the media you intend to use, or enter f to save the dump to /dumpfile. If /dumpfile already exists, you are asked to enter another name.

If you chose a separate dump device during installation, or later changed a dump slice (type V_DUMP; see vtoc(7)) on the root disk, the dump will just stay on that slice and you will not have to go through this procedure.