Managing Systems and Workgroups: A Guide for HP-UX System Administrators

Administering a System: Booting and Shutdown
Abnormal System Shutdowns
Chapter 5 543
NOTE For HP-UX releases prior to Release 11.0, dump device definitions must
be built into the kernel.
How Much Dump Space Do I Need? Before you define dump devices,
it is important to determine how much dump space you need, so that you
can define enough dump space to hold the dump, but will not define too
much dump space, which would be a waste of disk space.
Systems Running
HP-UX Releases
Prior to Release
11.0
The decision for systems running HP-UX Releases prior to Release 11.0
is pretty simple: How much physical memory is in your system? The
concept of a “selective dump” was introduced at Release 11.0. Prior to
that time, dumps are full memory dumps (if dump space permits).
So, define enough dump space to total the amount of physical memory in
your system.
Systems Running
HP-UX Release
11.0 or Later
For HP-UX Releases 11.0 and later, the amount of dump space you need
to define is also equal to the size of your system’s physical memory if you
want to have a full dump saved.
For selective dumps, the size of your dump space varies, depending on
which classes of memory you are saving. There is an easy way to
estimate your needs:
Step 1. When the system is up and running, with a fairly typical work load, run
the following command:
/sbin/crashconf -v
You will get output that looks similar to the following:
CLASS PAGES INCLUDED IN DUMP DESCRIPTION
-------- ---------- ---------------- -------------------------------------
UNUSED 2036 no, by default unused pages
USERPG 6984 no, by default user process pages
BCACHE 15884 no, by default buffer cache pages
KCODE 1656 no, by default kernel code pages
USTACK 153 yes, by default user process stacks
FSDATA 133 yes, by default file system metadata
KDDATA 2860 yes, by default kernel dynamic data
KSDATA 3062 yes, by default kernel static data
Total pages on system: 32768