The DGM provides the following functionalities:

•Sends a notification message upon the change in a device group status.

•Performs automatic resynchronization of the Continuous Access device group upon link recovery.

•In case of a Tri-Link configuration, it performs automatic resynchronization of the Delta Resync pair upon some of the failures that result in data not being replicated over the active Continuous Access Journal pair to the third data center (DC3).

In the 3DC environment, where the device group state is not actively monitored, it may not be apparent when the application data is not remotely protected for an extended period of time. For example, there is a link failure between DC1 and DC2. If DGM is not configured, this link failure may go unnoticed and this will cause data loss at DC2 upon DC1 failure. Similarly, for example, if the data is being replicated from DC1 to DC2 and then from DC2 to DC3, and there is a link failure between DC2 and DC3, it results in data not being replicated to DC3. The DGM identifies link failure, notifies the user, and performs appropriate actions based on the monitor’s parameter settings.

Configuring DGM is optional but strongly recommended. The DGM runs as a package service. The user can configure the monitor's setting through the DGM specific parameters in the package configuration file. Once the package has started the DGM, the monitor periodically checks the status of the device pairs configured in the package. If there is a change in the status or if the monitor is configured to notify after an interval of no status change, the monitor sends a notification to the user via e-mail, syslog, and console. The notification message states the reason for the notification, a timestamp, and the status of the device groups.

Infrastructure Requirements

Following are the infrastructure requirements for configuring any application in 3DC DR Solution:

•Ensure that the port number used by HP-UX Secure Shell is open for communication across three data centers. Nodes in all the three data centers must be able to communicate over the network.

•The replication links must be available among the three P9000 or XP arrays if it is a 3DC Tri-Link configuration. For 3DC Bi-Link configuration, the replication link must be available between the P9000 or XP arrays located in the Metrocluster region, and the replication link must be established between one of the P9000 or XP Disk Arrays located in the Metrocluster, and the recovery cluster at the third site.

•In case of 3DC Tri-Link configuration using Delta Resync, remote command devices must be created on each P9000 or XP array for the other two P9000 or XP arrays by using P9000 or XP External Storage Software. For information on creating a remote command device, see the HP StorageWorks P9000 External Storage for Open and Mainframe Systems User Guide or HP Storage-Works XP24000/XP20000 External Storage Software User's Guide available at http://bizsupport1.austin.hp.com/bizsupport/TechSupport/ProdSearch.jsp? prod=HP%20StorageWorks.

Configuring an P9000 or XP 3DC DR Solution

After the hardware set up is completed for all three data centers including the infrastructure requirements as specified in “Infrastructure Requirements” (page 429), the next step is the software installation and configuration. The cluster software used in a 3DC DR Solution includes Serviceguard clusters, Metrocluster with Continuous Access for P9000 and XP, Continentalclusters, and HP StorageWorks RAID Manager.

Complete the following procedures to configure an application in a 3DC DR Solution:

1.Install the required software on all nodes in the 3DC DR Solution.

2.Configure the primary cluster (Metrocluster).

Infrastructure Requirements 429