Building Disaster Recovery Serviceguard Solutions Using Metrocluster with EMC SRDF

the HP-UX path only to determine the Symmetrix device you are referring. The Symmetrix
device can be added to the device group only once.
NOTE: Symmetrix Logical Device names must be the default names in the DEVnnn (for
example, DEV001) format. Do not use this option for creating your own device names.
The script mk3symgrps.nodename must be customized for each system including:
• Particular HP-UX device file names.
• Symmetrix device group name (an arbitrary, but unique name may be chosen for each group
that defines all of the volume groups (VGs), which belong to a particular Serviceguard
package).
• Keyword RDF1 or RDF2.
Configuring Gatekeeper devices
Gatekeeper device is a special LUN through which host communicates with Symmetrix storage.
Gatekeeper devices are unique to a Symmetrix unit. They are not replicated across the SRDF link.
Gatekeeper devices are marked GK in the syminq output, and are usually 2880 KB in size.
Gatekeeper devices must be unique per the Serviceguard package to prevent contention in the
Symmetrix when commands are run, such as two or more packages starting up at the same time.
NOTE: The sample scripts mk4gatekpr.nodename can be modified to automate these steps.
1. Define at least two gatekeepers per package per node (assuming PV links are used). They
will only be available for use by that node. Each gatekeeper device is configured on different
physical links.
# symgate -sid sidnumber1 define dev devnumber1
# symgate -sid sidnumber2 define dev devnumber2
2. Associate the gatekeeper devices with the Symmetrix device group for that package.
# symgate -sid sidnumber1 -g devgroupname associate dev devnumber1
# symgate -sid sidnumber2 -g devgroupname associate dev devnumber2
3. Define a pool of four or more additional gatekeeper devices that are not associated with any
particular node. The EMC Solutions Enabler switches to an alternate gatekeeper device if the
path to the primary gatekeeper device fails.
Configuring a device group for SRDF/asynchronous
To perform an operation on a device group for SRDF/asynchronous data replication, the device
group must be configured with all the devices that are SRDF/Asynchronous capable within the
RDF group.
To create a device group:
1. List SRDF/Asynchronous capable devices on the source Symmetrix unit and be sure the
SRDF/Asynchronous capable devices are mapped to RDF group for use. In addition, all RDF
devices that belong to the RDF (RA) group must be configured in one device group for
SRDF/Asynchronous operation.
For example, use the following command to display the devices from RDF (RA) group number
2:
# symrdf -sid <symmid> list -rdfa -rdfg 2
Symmetrix ID: 000192603928
Local Device View
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Setting up a 1 by 1 configuration 17