Example configuration for SRDF management

This example assumes that your environment consists of a mutual recovery configuration in which a production site stores different applications and services, and a recovery site acts as an associated backup site.

The following configuration is required to implement a mutual recovery configuration:

• Two PowerHA® SystemMirror® sites, which are the same as a single recovery configuration
• Two resource groups, with each resource group configured to use mirrored storage

In PowerHA SystemMirror, you can configure two sites and a resource group that includes nodes, SRDF-managed replicated resources, and the volume groups that are associated with the replicated resources.

The SYMCLI client is installed on the PowerHA SystemMirror hosts and on each of the PowerHA SystemMirror managed nodes. The EMC SRDF operations are completed by using the SYMCLI software on a AIX® server. You can use the SYMCLI software on the AIX server to display EMC SRDF information and run SRDF operations from the command line or with a script file.

An SRDF replicated resource contains the EMC disk volume pairs (composite group) information. The PowerHA SystemMirror resource group definition includes the volume groups that are built on SRDF replicated volumes. PowerHA SystemMirror manages SRDF processing by dynamically running the SYMCLI commands.

Example for traditional SRDF configuration

The following image displays a typical implementation of two EMC VMAX storage with SRDF in a four-node PowerHA SystemMirror geographic cluster. The cluster consists of four IBM® Power Systems™ servers. Each storage device is connected to a node (Server A, Server B, Server C, and Server D) through SCSI or Fibre Channel links. The SRDF links are established between the Primary storage and the Secondary storage. The configuration also includes point-to-point networks for heartbeating to connect the cluster nodes together.

The order of the nodes in each resource group’s node list indicates which site is considered as the production site and which site is considered as the backup site for that resource group.

In the following figure the configuration for resource group 1 is as follows:

Ordered site list

Production site, Recovery site

Ordered node list

Server A, Server B, Server C, and Server D

The data mirroring goes from Primary storage, which is owned by the Production site, to the Secondary storage, which is owned by the Secondary site.

Example for EMC SRDF/Metro SmartDR configuration

Figure 2 displays a typical implementation of EMC SRDF/Metro SmartDR configuration with three EMC VMAX storage devices in a four-node PowerHA SystemMirror geographic cluster. The primary storage consists of two VMAX storage devices that are connected to production site nodes. The secondary storage is connected to recovery site nodes.

SRDF/Metro links are established between the primary storage and the secondary storage. The SRDF/Metro SmartDR configuration also includes point-to-point networks to connect the cluster nodes for heartbeating.