Migrating an existing complex into a sysplex

You can migrate an existing global resource serialization complex into a sysplex one system at a time. There are two ways you can accomplish the migration. The easier way is to add communication links for XCF to use in addition to the links already dedicated to global resource serialization. Providing the extra links allows you to keep your complex operational in the event that you encounter an unexpected situation and need to revert to the previous environment. Once your operating environment is stable after the migration, however, you can release the links that were dedicated to global resource serialization, freeing them for other uses.

Another way to migrate the systems in a complex into a sysplex requires releasing a link that is dedicated to global resource serialization and using that link for XCF, as well as providing every pair of systems in the complex with one additional link, also for XCF. The additional link between each pair of systems leaves one link dedicated to global resource serialization, enabling you to return to the previous environment with at least minimal link connections still dedicated to global resource serialization if an unexpected situation should make it necessary.

Note: You must use the VARY ctc,OFFLINE,FORCE command to release a CTC dedicated to global resource serialization before XCF can use the CTC.

The following example illustrates this migration technique. Figure 1 represents a fully-connected global resource serialization complex before migration described in the example begins.

Figure 1. Global Resource Serialization Complex before Migration

The systems are migrating to the next release sequentially, beginning with SYS1.

Migrating SYS1 into the sysplex
- All links remain dedicated to global resource serialization.
- ReIPL SYS1 into the sysplex.
Migrating SYS2 into the sysplex
- Remove one link (A11 in this example) from use by global resource serialization and make it available to XCF.
  - On SYS1, issue the VARY A11,OFFLINE,FORCE command so global resource serialization can no longer use the link. (Respond free to message ISG186D.)
  - On SYS1, issue the VARY A11,ONLINE command to make the link available to XCF.
  - On SYS1, issue the SETXCF START,PATHIN,DEVICE=(A11) command to let XCF begin using the link.
- Make another link (A12 in this example) available to XCF.
  - On SYS1, issue the SETXCF START,PATHOUT,DEVICE=(A12) command to let XCF begin using this new link.
- ReIPL SYS2 into the sysplex, specifying that XCF on SYS2 use links A11 and A12.
Migrating SYS3 into the sysplex
- Remove one link (B11) between SYS1 and SYS3 from use by global resource serialization and make it available to XCF.
  - On SYS1, issue the VARY B11,OFFLINE,FORCE command so global resource serialization can no longer use the link. (Respond free to message ISG186D.)
  - On SYS1, issue the VARY B11,ONLINE command to make the link available to XCF.
  - On SYS1, issue the SETXCF START,PATHIN,DEVICE=(B11) command to let XCF begin using the link.
- Make another link (B12 in this example) between SYS1 and SYS3 available to XCF.
  - On SYS1, issue the SETXCF START,PATHOUT,DEVICE=(B12) command to let XCF begin using this new link.
- Remove one link (D11) between SYS2 and SYS3 from use by global resource serialization and make it available to XCF.
  - On SYS2, issue the VARY D11,OFFLINE,FORCE command so global resource serialization can no longer use the link. (Respond free to message ISG186D.)
  - On SYS2, issue the VARY D11,ONLINE command to make the link available to XCF.
  - On SYS2, issue the SETXCF START,PATHIN,DEVICE=(D11) command to let XCF begin using the link.
- Make another link (D12) between SYS1 and SYS3 available to XCF.
  - On SYS2, issue the SETXCF START,PATHOUT,DEVICE=(D12) command to let XCF begin using this new link.
- ReIPL SYS3 into the sysplex, specifying that XCF on SYS3 add and use links B11, B12, D11, and D12.
Migrating SYS4 into the sysplex
- Remove one link (C11) between SYS1 and SYS4 from use by global resource serialization and make it available to XCF.
  - On SYS1, issue the VARY C11,OFFLINE,FORCE command so global resource serialization can no longer use the link. (Respond free to message ISG186D.)
  - On SYS1, issue the VARY C11,ONLINE command to make the link available to XCF.
  - On SYS1, issue the SETXCF START,PATHIN,DEVICE=(C11) command to let XCF begin using the link.
- Make another link (C12) between SYS1 and SYS4 available to XCF.
  - On SYS1, issue the SETXCF START,PATHOUT,DEVICE=(C12) command to let XCF begin using this new link.
- Remove one link (E11) between SYS2 and SYS4 from use by global resource serialization and make it available to XCF.
  - On SYS2, issue the VARY E11,OFFLINE,FORCE command so global resource serialization can no longer use the link. (Respond free to message ISG186D.)
  - On SYS2, issue the VARY E11,ONLINE command to make the link available to XCF.
  - On SYS2, issue the SETXCF START,PATHIN,DEVICE=(E11) command to let XCF begin using the link.
- Make another link (E12) between SYS2 and SYS4 available to XCF.
  - On SYS2, issue the SETXCF START,PATHOUT,DEVICE=(E12) command to let XCF begin using this new link.
- Remove one link (F11) between SYS3 and SYS4 from use by global resource serialization and make it available to XCF.
  - On SYS3, issue the VARY F11,OFFLINE,FORCE command so global resource serialization can no longer use the link. (Respond free to message ISG186D.)
  - On SYS3, issue the VARY F11,ONLINE command to make the link available to XCF.
  - On SYS3, issue the SETXCF START,PATHIN,DEVICE=(F11) command to let XCF begin using the link.
- Make another link (F12) between SYS3 and SYS4 available to XCF.
  - On SYS3, issue the SETXCF START,PATHOUT,DEVICE=(F12) command to let XCF begin using this new link.
- ReIPL SYS4 into the sysplex, specifying that XCF on SYS4 add and use links C11, C12, E11, E12, F11, and F12.

Figure 2 shows the same complex after migration, but before the links dedicated to global resource serialization are released.

Figure 2. Global Resource Serialization Complex after Migration

The final step, once you are satisfied that your sysplex is performing normally, is to release the links that remain dedicated to global resource serialization. Use the VARY device,OFFLINE,FORCE command and respond free to message ISG186D for each link that you wish to free on each system. Using the sysplex shown in Figure 2, you would issue the VARY device,OFFLINE,FORCE command:

On SYS1 to release links A10, B10, and C10
On SYS2 to release links A10, D10, and E10
On SYS3 to release links B10, D10, and F10
On SYS4 to release links C10, E10, and F10.