By default,
Release Patch Kits are made reversible during the installation so
you revert your system to its state prior to the installation. If
you choose to make patch kits nonreversible, you will not be able
to uninstall the kit.
Customer-Specific patch kits are forced
to be reversible when the CSP kit is manufactured. This forced reversibility
overrides the reversibility option provided by dupatch during installation.
Patch reversibility
is dependent upon saving the existing system files that will be updated
by the patch. Saving these files requires the availability of adequate
storage space in /var/adm/patch/backup, which
can be a mount point for a separate disk partition, an NFS mount point,
or a symbolic link to another file system. This allows you to configure
your system to reduce the impact on system disk space for the /, /usr, and /var partitions.
The dupatch utility checks for
the required storage space prior to patch installation. Patch installation
is prevented if adequate backup space is unavailable.
“Performing a Patch Preinstallation Check” includes
an example of the dupatch output regarding patch
reversibility.