Recover Quorum Operation; Best Practices For Configuring Quorum And Managers In A Multi-Site San Environment; Common Multi-Site San Configurations With Recommended Managers - HP StorageWorks P4000 User Manual

Failure condition
Primary site offline

Recover quorum operation

The Recover Quorum function is introduced with the Multi-Site SAN as a way to bring volumes back
online in the event that quorum in the management group is lost.
CAUTION:
The Recover Quorum function should only be used as a last resort. The failed site must be completely
failed to use Recover Quorum safely on the remaining site.
The Recover Quorum command-line function performs the following actions:
1. Removes all offline managers from the management group.
2. Ejects all offline storage systems from the management group.
3. The SAN/iQ software is modified to prevent any data integrity issues in the event any of the
offline storage systems are brought back online.
Best practices for configuring quorum and managers in a Multi-Site SAN
environment
Configuring the appropriate number of managers in a Multi-Site SAN on the appropriate storage
systems is an important part of setting up the Multi-Site SAN for high availability and fault tolerance.
Table 6 on page 20 identifies common Multi-Site SAN configurations and the recommended manager
configurations.
Table 6 Common Multi-Site SAN configurations with recommended managers
Multi-Site SAN configuration
Two physical sites, one site is
primary
20 Designing a Multi-Site SAN
Resolution steps
1. If any of the storage systems running managers in the primary
site can be brought back online, you should do this first.
2. If all storage systems in the primary site are lost forever, you
can use the Recover Quorum command-line function to recover
quorum in the secondary site manually. For more information,
see "Recover quorum operation," next in this section
Manager configuration
For four storage systems, run:
two managers in the primary
site
one manager in the secondary
site
For six storage systems or more,
run:
three managers in the primary
site
two managers in the secondary
site
Number of managers and num-
ber Needed to maintain quorum
Manager count = three
Number for quorum = two
Manager count = five
Number for quorum = three