You can dynamically activate and deactivate some service items (PTFs, ++APARs, ++Usermods) that affect the z/OS UNIX component modules without having to reIPL. This capability is primarily intended to allow an installation to activate corrective service to avoid unplanned reIPLs of your systems. Additionally, this capability can be used to activate temporary code that can be used in gathering additional documentation for a recurring system problem. Although this capability can be used to activate preventive service on an ongoing basis, it is not intended for this purpose.

Those PTFs that are capable of being activated dynamically will have ++HOLD REASON(DYNACT) included within their PTF. Additionally, any ++USERMOD or ++APAR provided from IBM® will have explicit instructions provided by the IBM Service Team indicating whether the ++Usermod or ++APAR can be dynamically activated. Although a service item might be identified as being capable of dynamic activation, the level of a given system might not be current enough to allow the activation of the service item. The ++HOLD REASON(DYNACT) will identify the service level required to activate the PTF. In order to properly activate the PTF, follow the directions in the ++HOLD in the PTF.

Restriction: Dynamically activating a PTF on top of a superseded ++APAR is not allowed. If the ++APAR was activated dynamically, you can deactivate it and then activate the PTF. Otherwise, the PTF will need to be applied with an IPL.

In order to be prepared to exploit dynamic service activation, you must stay current on z/OS UNIX Component maintenance. Staying current makes it more likely that any given service item can be activated dynamically, because the running system will be at a high enough level to accept the service item. On a periodic or as-needed basis, you will have to determine the selected PTFs that you would be interested in activating dynamically for corrective purposes. These would likely be the PTFs that are of highest severity and highest impact related to your workloads.

To ensure that you activate only those service items that are of interest, it is recommended that you additionally install these service items into a separate load library from the LPALIB or LINKLIB libraries that are used for your normal install process. You can copy (or clone) the SMP/E environment for the currently running z/OS® system and then install the applicable PTFs using the cloned SMP/E environment and cloned target libraries. The applicable PTFs are the ones that have been identified with ++HOLD REASON(DYNACT).