Overview of MetroCluster/SRDF

MetroCluster is a set of scripts and an environment file that work in an MC/ServiceGuard cluster to automate failover to alternate nodes in the case of disaster in a campus or metropolitan cluster. The MetroCluster/SRDF product contains the following files.

Table 4-1 MetroCluster/SRDF Template Files

Name	Description
`/opt/cmcluster/toolkit/SGSRDF/srdf.env`	The MetroCluster/SRDF environmental file. This file must be customized for the specific EMC Symmetrix and HP 9000 host system configuration. Copies of this file must be customized for each separate MC/ServiceGuard package.
/opt/cmcluster/toolkit/SGSRDF/samples	A directory containing sample convenience shell scripts that must be edited before using. These shell scripts may help to automate some configuration tasks. These scripts are contributed, and not supported.
/usr/sbin/DRCheckDiskStatus	The script that checks for a specific environment file in the package directory and should not be edited.
/usr/sbin/DRCheckSRDFDevGrp	The script that checks the status of the SRDF device group that is used by the package and should not be edited.

MetroCluster/SRDF has to be installed on all nodes that will run a ServiceGuard package that accesses data on an EMC Symmetrix where the data are replicated to a second Symmetrix using the SRDF facility. In the event of node failure, the integration of MetroCluster/SRDF with the package will allow the application to fail over in the following ways:

among local host systems that are attached to the same EMC Symmetrix.
between one system that is attached locally to its EMC Symmetrix and another "remote" host that is attached locally to the other EMC Symmetrix.

MetroCluster with Symmetrix SRDF is specifically for configuring one or more MC/ServiceGuard packages whose data reside on EMC Symmetrix ICDAs (Integrated Cache Disk Arrays) replicated with SRDF (Symmetrix Remote Data Facility).

MetroCluster with Symmetrix SRDF can be used in a campus or metropolitan cluster configuration with nodes in a loop of up to 100 km. Symmetrix configurations can be either 1 by 1 (one Symmetrix at each data center) or M by N (one or two Symmetrix frames at each data center).

Configuration of MetroCluster/SRDF must be done on all the cluster nodes, as is done for any other MC/ServiceGuard package. To use MetroCluster/SRDF, Symmetrix host-based software for control and status of the EMC Symmetrix disk arrays must also be installed and configured on each HP 9000 host system that might execute the application package.

Overview of MetroCluster/SRDF

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