Installation guide

Saving Memory Dumps
5-52 Fault Tolerant System Administration (R1004H) HP-UX version 11.00.03
Preventing the Loss of a Dump
To prevent losing a dump after system interruption, if you configured the system
to use savecrash as the default dump utility, or if a crash occurs when the system
is in simplex mode, you need to do the following:
■ configure the primary and secondary swap partitions with the Mirror
Write Cache option disabled and Mirror Consistency Recovery
option disabled.
■ Issue the lvcreate with the -M and -c options
■ In large-memory systems, you need to set the largefiles flag when creating
file systems. Otherwise, save_mcore will not be able to perform a 4-GB
dump. To set this flag, enter
fsadm –F vxfs –o largefiles file_system
In some circumstances, such as when you are using the primary paging device
along with other devices as a dump device, you care about what order they are
dumped to following a system crash. In this way you can minimize the chances
that important dump information will be overwritten by paging activity during
the subsequent reboot of your computer.
No matter how the list of currently active dump devices is built (from a kernel
build, from the /etc/fstab file, from use of the crashconf command, or any
combination of these) dump devices are used (dumped to) in the reverse order
from which they were defined. In other words, the last dump device in the list is
the first one used, and the first device in the list is the last one used. Therefore, if
you have to use a device for both paging and dumping, it is best to put it early in
the list of dump devices so that other dump devices are used first.