Ownership takeover mode for the IBM® TS7700 family enables another cluster in a grid configuration to take immediate control of a failing cluster's currently owned virtual volumes. When the cluster comes back online, you must reconcile changes in data before you can reuse the cluster. This reconciliation ensures that each of the clusters’ virtual volume copies are updated with the latest changes.
Let us use an example to help you understand how to enable ownership takeover mode. Assume weather conditions have caused a production site outage at the New York site. The New York cluster replicated volumes to the Arabian site where a standby host is available. To access volumes previously owned by the New York site from the Arabian cluster standby host, ownership takeover must first be enabled at the Arabian location against the New York site. This will allow the Arabian location to assume ownership, as needed, of volumes last accessed by New York.
To view and edit settings for Ownership Takeover Mode, select Ownership Takeover Mode from the Service menu. A message is displayed to remind you that manually setting Ownership Takeover Mode is not generally recommended unless you are sure the unavailable cluster is in fact not operational. Autonomic Ownership Takeover manager can be enabled to automate this process so that manual intervention is not required.
Next, select the failed cluster within the grid.
Click Select Action for the failed cluster and then select Set Read/Write Virtual Volume Ownership Takeover from the list.
A confirmation message is displayed. Click OK. Ownership takeover mode is now enabled against the unavailable cluster.
This has been a brief overview of using ownership takeover mode. For additional information, see the other topics in IBM Knowledge Center.