Software Distributor Administration Guide for HP-UX 11i

Reliability and Performance
Recovery (Install Only)
Chapter 8250
Recovery (Install Only)
NOTE This section applies only to customer-created software with unpreinstall
and unpostinall scripts. HP-supplied software does not include these
scripts.
SD-UX supports automatic procedures to recover from failed installation
if the autorecover_product option is set to true, attempting to leave the
system in the same state as it was previously. Also, manual means are
available (refer to “Multiple Versions” on page 253).
Rollback is limited to the system where the installation of the product
failed, not all target systems specified in an installation job.
Because autorecovery removes any files that were installed up to this
point, it is antithetic with the checkpointing and retry features
previously described. Recovery saves copies of each file that it is
replacing, then removes those files at the successful completion of the
product installation. If the install fails, then the saved files are restored.
Once a product is successfully updated, it cannot be restored except by
reinstalling it. Additionally, if a later product fails, the earlier product
cannot be recovered. In order to meet the requirement that multiple
products be recoverable, multiple versions must be installed.
The unpreinstall and unpostinstall scripts are needed to undo the steps
that the preinstall and postinstall scripts executed. The normal sequence
of operations for each product is:
1. Execute the product preinstall script
2. For each fileset
a. execute the preinstall script
b. install the files
c. execute the postinstall script
3. Execute the product postinstall script