Creating live-system dumps with zgetdump

If you require a kernel dump of a Linux®, but no downtime is acceptable, you can create a kernel dump from a live system without disruption.

Because the Linux system continues running while the dump is written, and kernel data structures are changing during the dump process, the resulting dump contains inconsistencies. The faster the dump process completes, the fewer inconsistencies the resulting live-system dump will contain. Therefore, run the dump process with the highest acceptable priority.

You can change the scheduling priority with the nice command. For example, use nice -n -20 to set the highest possible priority.