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

Administering a System: Booting and Shutdown
Abnormal System Shutdowns
Chapter 5 537
(A dump that previously took 3 hours to complete should now take only 1
hour.)
• You can use the crashconf(1M), command to disable or enable compressed
dumps. (Compression is configured into the kernel by default.) During a
crash event, you can also choose to override dump compression.
Normally, there is no benefit in disabling compression unless the initial
(compressed) dump is corrupt and you want to attempt an uncompressed
dump on a subsequent crash event.
• You can convert the compressed dump file to any of the previous dump
formats for storage and analysis.
• The compressed dump file requires less disk storage space and creates a
smaller tar file that takes less time to copy to tape or to transmit for
analysis by using the ftp program.
• In HP-UX 11i v2, the progress of memory dumps is updated at least once
every 15 seconds. This change reduces the dump time.
Restrictions on
Compressed Dumps
• compression settings described in “Compressed Save versus Noncompressed
Save” on page 539 are ignored.
The following restrictions apply to this release:
• If your system uses virtual partitions (vPars), the dump might not be
compressed but the dump process will continue.
• If more than one crash occurs in close succession, it might not be possible for
the system to compress the dump.
If either of the preceding conditions apply, the following messages are displayed
at the console:
*** Recursive crash.
*** Dump defaulting to sequential without compression
Configuring
Compressed Dumps
In HP-UX Release 11i version 1.0, compression is enabled in the kernel by
default. You can disable (and enable) the feature by using the crashconf dump
configuration utility. Use the -c option with the on argument to control the
status of compressed dumps, as follows:
$ crashconf -c on
Use the -v option to examine the status of compressed dumps, as follows:
$ crashconf -v
{Lines omitted from display}
Dump compressed: ON