Example of activating modified PSBs in subsets of systems in an IMSplex

The following series of figures illustrate the gradual activation of a modified PSB across the systems within an IMSplex.

The IMSplex consists of five IMS systems, an IMS catalog with directory and staging data sets, and the Operations Manager (OM) of the IMS Common Service Layer (CSL). All of the IMS systems share the ACBs in the IMS catalog and directory data set, as indicated by the specification of ACBSHR=Y.

In the example, PSB1 is updated. The original version of PSB1 has a time stamp that is represented in the figures by ts01. The updated version of PSB1 has a later time stamp that is represented by ts02.

In the first figure of the series, the original version of PSB1 with time stamp ts01 is running in three IMS systems in the IMSplex: IMS1, IMS3, and IMS5. IMS2 is down and IMS4 defines PSB1 as non-resident and does not currently have a copy in a buffer or 64-bit storage. The new version of PSB1 with time stamp ts02 is ready to be activated after it is placed in the staging data set and the IMS catalog.

Figure 1. Initial state of PSB1 in the IMSplex before a new version is activated
Five IMS systems are show across the top of the image. They all show ACBSHR=Y. IMS1, IMS3, and IMS5 show PSB1 with time stamp tso2 loaded. IMS2 is down. IMS4 does not have PSB1 loaded because PSB1 is defined with RES=N. Operations Manager is in the lower left area. The IMS catalog contains PSB1 ts01 and PSB1 ts02. The directory contains PSB1 ts01. The staging data set contains PSB1 ts02.

In the following figure, the command IMPORT DEFN SOURCE(CATALOG) OPTION(UPDATEPSB) FOR(IMSID(IMS1)) is issued to activate the new version of PSB1 with time stamp ts02 on IMS1 only. To activate PSB1 on only IMS1, the command is both explicitly routed to IMS1 and specified in the FOR keyword. However, PSB1 is also considered activated on IMS4 because IMS4 defines PSB1 as non-resident and does not currently have a copy of PSB1 in memory. IMS4 reloads PSB1 from the IMS directory the next time the PSB is scheduled.

Because IMS3 and IMS5 are not included in the FOR keyword of the command, they do not refresh PSB1 and continue to use the original version that they have in memory. The output of the IMPORT DEFN command shows that a refresh is pending for PSB1 on IMS3 and IMS5.

Figure 2. The new version of PSB1 is activated on IMS1. IMS2 loads the new version on scheduling.
The figure is described in the preceding text.

In the following figure, IMS2, which was down when the IMPORT DEFN SOURCE(CATALOG) OPTION(UPDATEPSB) FOR(IMSID(IMS1)) command, restarts. IMS2 is unaffected by the command and loads the new version of PSB1 from the IMS directory during restart.

Figure 3. IMS2 loads PSB1 during restart
Figure is described in the preceding text.

In the following figure, the command IMPORT DEFN SOURCE(CATALOG) OPTION(REFRESHPSB) FOR(IMSID(IMS3)) is issued to activate the new version of PSB1 with time stamp ts02 on IMS3 only. To activate PSB1 on IMS3, the command is explicitly routed to IMS1 although IMS3 is specified in the FOR keyword. When the REFRESHPSB option is specified, the IMS systems that are specified on the FOR keyword cannot serve as the command master.

Figure 4. The REFRESHPSB option activates the new version of PSB1 on IMS3
The figure is described in the preceding text.

In the following figure, IMS5 restarts. Before restarting, IMS5 had the original version of PSB1, which was in a refresh-pending state, loaded. However, during the restart, the refresh-pending state is removed and the new version of PSB1 is loaded from the IMS directory.

Figure 5. IMS5 restarts and loads the new version of PSB1
The figure is described in the preceding text.