Deferred Activation Patching (6486471)

Starting with patch 119254-42 and 119255-42, the patch installation utilities, patchadd and patchrm, have been modified to change the way that certain patches delivering new features or existing files that are incompatible with the running system are handled. This utilities modification affects the installation of these patches on any Solaris 10 release. These “deferred-activation” patches handle the large scope of change delivered in Kernel patches better.

In deferred Activation patching, a loopback file system, lofs, is used to create a copy of the root file system. The original files being patched are copied to a safe location and the lofs copy of the root file system is patched. Then the original file is lofs mounted back over the new file as it is patched. This means the running system remains consistent over the duration of patching, new features are not active and any incompatible change is hidden until the user reboots.

Users must reboot as soon as possible after applying a Deferred Activation Patch, but they do not have to reboot immediately, they can still add further patches then reboot.

The patch README provides instructions on which patches require a reboot.

Note –

Sun strongly recommends that patch operations are carried out in a single-user mode, especially when this is recommended by the patch README.

If you are running non-global zones or have lofs disabled, consider the following points when installing or removing deferred-activation patches:

All non-global zones must be in a halted state for this patch operation. You must halt the non-global zone before applying the patch.
Deferred-activation patching requires the loopback file system, lofs in order to complete successfully. Systems running Sun Cluster 3.1 or Sun Cluster 3.2 are likely to have lofs turned off because of restrictions on HA-NFS functionality when lofs is enabled. Therefore, before a deferred-activation patch is installed, you must re-enable the loopback file system by performing the following steps.
1. Remove or comment out the following line in the /etc/system file:
  exclude:lofs
2. Reboot your system.
3. Install the patch.
4. After you have completed the patch installation operation, restore or uncomment the same line from the /etc/system file.
5. Reboot the system to resume normal operations.

No error message is displayed.

Workaround: Sun recommends Solaris Live Upgrade to manage patching. Solaris Live Upgrade prevents the problems of patching a running system. Solaris Live Upgrade reduces the amount of downtime involved in patching and reduces risk by providing fallback capability if problems occur. For more information, see Solaris 10 10/08 Installation Guide: Solaris Live Upgrade and Upgrade Planning.