Software Distributor Administration Guide for HP-UX 11i

Reliability and Performance
Compression
Chapter 8246
Compression
The swinstall and swcopy commands can transfer large amounts of data
over the network from depots to targets. The SD-UX compress_files
option can improve performance by first compressing files that are to be
transferred. This can reduce network usage by approximately 50%; the
exact amount of compression depends on the type of files. Binary files
compress less than 50%; text files generally compress more.
Set this option to true only when network bandwidth is clearly
restricting total throughput. If it is not clear that this option will help,
compare the throughput of a few swinstall or swcopy tasks (i.e., with and
without compression) before changing this option value.
You can use swcopy to compress files and leave them compressed in a
target depot or compress before network transfer and uncompress
afterward.
Precompressing a depot is advantageous when installing or copying to
multiple targets. If the source depot is not already compressed, then each
file is recompressed for each target.
You can set uncompress_files to true to leave a depot uncompressed
after copying with swcopy. For swinstall, the compress_files option will
compress all uncompressed files before network transfer. Files are
always uncompressed before installing them to the target file system.
INDEX and INFO Compression
Another way to reduce your network traffic is by compressing INDEX
and INFO files from the source depot to the target. You can turn on
INDEX or INFO compression by setting the compress_index option to
true in the defaults file (/var/adm/sw/defaults).
The SD-UX controller and target agents will request compressed INDEX
files from the source agent. If the source agent is read only or an older
version of SD-UX, the agent cannot comply; consequently, the client will
request a normal INDEX. Otherwise, the source agent will send a
precompressed INDEX and INFO or compress it on the fly.
The target agent will then create a permanent compressed INDEX in the
target, depot, or root. This saves the next request for a compressed
INDEX or INFO from having to compress on the fly.