Merging clusters

You can add an existing TS7700 Cluster to an existing TS7700 Grid or to another existing TS7700 Cluster to form a grid for the first time.

An installed and operational TS7700 Cluster that contains data can be merged with a previously installed and operational TS7700 Cluster or TS7700 Grid. Refer to the topic Adding TS7700 Clusters to a grid in the Related information section for available cluster merge scenarios.
Important: You cannot insert or eject any virtual or physical volumes during a grid join. Do not begin the merge operation until all insert and eject operations are complete on all clusters in both grids.

FC 4015, Grid enablement must be installed on all TS7700 Clusters that operate in a grid configuration.

You might need to access the merging cluster before it becomes part of a grid (for example, to remove duplicate volumes that would prevent a successful grid join). Plan to complete any access to the soon-to-be merged (stand-alone) cluster before initiating any host configuration changes. Plan for the following host configuration changes, which must be completed before using the newly-joined cluster:
  • All HCDs (hardware configuration definition: the MVS [multiple virtual storage] component that builds the I/O definitions), subsystem IDs, and Port IDs must be updated.
  • The RMM (Removal Media Manager) and volcat (volume category) ranges must be updated within their respective storage groups. These ranges must be unique to ensure that the merge proceeds as expected. Updating the ranges is necessary to maintain continued access to the original volumes that were created when the system(s) were configured as stand-alone cluster(s).
Plan to define the following management and data policies after the TS7700 Cluster merge is complete:
  • Define stacked volume ranges
  • Define scratch categories
  • Define the expired virtual volume data policy
  • Define inhibit reclaim schedule
    Note: Prior to microcode level 8.5.0.xx, inhibit reclaim schedules were designated by using local time instead of Coordinated Universal Time (UTC). If you have upgraded from a microcode level of 8.4.0.xx, verify that your inhibit reclaim schedule displays the correct day and time before you start an inhibit reclaim operation using the new code version.
  • Define reclaim threshold percentage
If categories and constructs are already defined on the merging cluster, verify that the total number of each category and construct that will exist in the grid following the merge does not exceed 256. If necessary, delete existing categories or constructs from the merging clusters before the grid join occurs.
Each TS7700 Grid supports a maximum of 256 of each of the following categories and constructs:
  • Scratch categories
  • Management Classes
  • Data Classes
  • Storage Classes
  • Storage Groups
Important: Each TS7700 Grid supports a maximum of four million virtual volumes (available with FC 5270). Verify that the total number of virtual volumes to exist in the grid following the merge does not exceed four million. If necessary, remove existing virtual volumes from the merging clusters before the grid join occurs. Verify that no duplicate VOLSERs exist between the merging clusters. Each cluster within the TS7700 Grid must have at least 16 GB of physical memory installed before four million virtual volumes are supported. Verify that each cluster possesses enough physical memory before merging clusters.