Designing Disaster Tolerant High Availability Clusters, 10th Edition, March 2003 (B7660-90013)

Physical Data Replication for ContinentalClusters Using EMC SRDF
Maintaining the EMC SRDF Data Replication Environment
Chapter 7 359
For example, if a package is configured to failover across four nodes
in the cluster, there should be eight gatekeeper devices (two for each
node) that are assigned to the Symmetrix device group belonging to
this package.
It is required that there be a pool of four additional gatekeeper
devices that are NOT associated with any device group. These
gatekeepers would be available for other, non-cluster uses, e.g., the
Symmetrix Manager GUI and other SymCLI or SymAPI requests.
After data configuration, each physical device in the Symmetrix has
enough space remaining on it for gatekeeper purposes.
• This toolkit does not support the HP OmniBack Integration with
Symmetrix. The OmniBack Integration with Symmetrix may create
certain states that will cause this package to halt if a failover occurs
while the backup is in progress.
• No checking of the status of the SA/FA ports is done. It is assumed
that at least one PVLink is functional. Otherwise, the VG activation
will fail.
• This toolkit may increase package startup time by 5 minutes or
more. Packages with many disk devices will take longer to start up
than those with fewer devices due to the time needed to get device
status from the Symmetrix. Clusters with multiple packages that
use devices on the Symmetrix will all cause package startup time to
increase when more than one package is starting at the same time.
• The value of RUN_SCRIPT_TIMEOUT in the package ASCII file should
be set to NO_TIMEOUT or to a large enough value to take into
consideration the extra startup time due to getting status from the
Symmetrix. See the previous paragraph for more information on the
extra startup time.