Building Disaster Recovery Serviceguard Solutions Using Metrocluster with EMC SRDF

Setting up the RDF daemon
The cycle switch process required for SRDF/Asynchronous MSC is provided by the Solutions Enabler
software executing an RDF daemon that implements the MSC functionality. You can enable or
disable the RDF daemon on each host using the SYMAPI_USE_RDFD option in the SYMAPI file.
The default value of the SYMAPI_USE_RDFD option is DISABLE. To enable the RDF daemon, set
the SYMAPI_USE_RDFD to ENABLE. Setting this option to ENABLE activates the RDF daemon for
SRDF/Asynchronous MSC. HP recommends that you enable the RDF daemon on multiple hosts.
Starting and stopping the daemon
There are multiple ways in which you can start the RDF daemon. You must start the daemon on all
the nodes in the cluster. If you have enabled the RDF daemon, the Solutions Enabler software
automatically starts the daemon. Alternatively, you can manually start the daemon using the
stordaemon command:
# stordaemon start storrdfd [-wait Seconds]
By default, the stordaemon command waits 30 seconds to verify that the daemon is running. To
override this default value, use the -wait option.
In addition, you can set the RDF daemon to start automatically every time the local host is started.
You can set this condition for the daemon using the following command:
# stordaemon install storrdfd -autostart
To stop the RDF daemon, run the following command:
# stordaemon stop storrdfd [-wait Seconds]
Creating the cluster
Create the cluster or clusters according to the process described in the http://www.hp.com/go/
hpux-serviceguard-docs —> HP Serviceguard —> Managing Serviceguard user’s guide. In the
case of a metropolitan cluster, create a single Serviceguard cluster with components on multiple
sites.
NOTE: Do not configure an SRDF device belonging to a device group as a cluster lock disk. A
cluster lock disk must always be writable. Since it cannot be guaranteed that either half of a paired
volume is always writable, neither half may be used as a cluster lock disk. A configuration with a
cluster lock disk that is part of a paired volume is not a supported configuration.
Site aware failover configuration
To use either of these policies: site_preferred_manual or site_preferred, the underlying
cluster must be configured with sites and each cluster node must be associated to a site. The
Serviceguard cluster configuration file includes the attributes described in Table 2 (page 26) to
define sites.
Table 2 Site aware failover configuration
DescriptionAttributes
To define a unique name for a site in the cluster.SITE_NAME
SITE keyword under the node's NODE_NAME definition.SITE
Following is a sample of the site definition in a Serviceguard cluster configuration file:
SITE_NAME san_francisco
SITE_NAME san_jose
SITE san_francisco
NODE_NAME SFO_2
SITE san_francisco
NODE_NAME SJC_1
26 Configuring an application in a Metrocluster solution