Installation guide

To compress a vmcore. n crash dump file, use a utility such as gzip,
compress,ordxarchiver. For example, the following command creates a
compressed file named vmcore.3.gz
% gzip vmcore.3
A vmzcore. n crash dump file uses a special compression method that
makes it readable by the current Tru64 UNIX debuggers and crash
analysis tools without requiring decompression. A vmzcore.
n file is
substantially compressed compared to the equivalent vmcore.
n file, but
not as much as if the latter had been compressed using a standard UNIX
compression utility such as gzip. Standard compression applied to a
vmzcore.
n file will make the resulting file about 40 percent smaller than
the equivalent vmzcore.
n file.
If you need to apply the maximum compression possible to a vmzcore.
n
file, perform the following steps:
1. Uncompress the vmzcore.
n file using the expand_dump command
(see expand_dump
(8)). The following example creates an uncompressed
file named vmcore.3 from the file vmzcore.3:
% expand_dump vmzcore.3
2. Compress the resulting vmcore. n file using a standard UNIX utility.
The following example uses the gzip command to create a compressed
file named vmcore.3.gz :
% gzip vmcore.3
_______________________ Note _______________________
• You can uncompress a vmzcore.
n file only with the
expand_dump command. (Do not use gunzip, uncompress,
or any other utility).
• After a vmzcore.
n file has been uncompressed into a
vmcore.
n file with expand_dump, you cannot compress it
back into a vmzcore.
n file.
13.6.6.2 Uncompressing a Partial Crash Dump File
Use care when uncompressing a partialcrash dump file that was
compressed from a vmcore.
n file. Using the gunzip or uncompress
command with no flags results in a vmcore
.n file that requires storage
space equal to the size of memory. In other words, the uncompressed file
requires the same amount of disk space as a vmcore.
n
file from a full
crash dump.
13–24 Administering Events and Errors