9.5 HP P4000 Multi-Site HA/DR Solution User Guide (AX696-96074, September 2011)

1 Designing a Multi-Site SAN
The Multi-Site SAN features enable you to synchronously mirror data between sites automatically.
You create a Multi-Site SAN by configuring equal numbers of storage systems into sites in the
software. The Multi-Site SAN software enables a variety of features that are based on geographic
awareness and synchronous replication:
• Multi-Site clusters that can:
Span up to three sites◦
◦ Span multiple subnets
◦ Have multiple VIPs
• Geographical awareness, enabled by designating storage systems as members of a particular
site.
• Synchronously replicated (mirrored) data between sites, based on volume data protection
level.
• Site information that ensures that data is mirrored between sites for high availability and
disaster recovery.
• I/O path preferencing, so that application servers connect to storage systems located in the
same site.
• Failover Manager support for automatic failover/failback in three-site configurations without
requiring a physical storage system in the third site.
• Failover Manager for quorum management if the network connection between the two sites
becomes unavailable.
• Recover quorum via CLI when a site failure also results in losing quorum in the management
group.
Failover Manager overview
The Failover Manager is a specialized version of the SAN/iQ software, designed to run as a
virtual appliance in a VMware environment. The Failover Manager participates in the management
group as a real manager in the system; however, it performs quorum operations only, not data
movement operations. It is especially useful in a Multi-Site SAN configuration to manage quorum
for the multi-site configuration without requiring additional physical hardware at a site.
The Failover Manager is supported on VMware Server, Workstation, and Player. For detailed
information about installing and configuring the Failover Manager, see “Using Specialized
Managers” in the HP P4000 SAN Solution User Guide.
Requirements
• A Multi-Site SAN requires a feature key for each storage system in the management group
that is also participating in a Multi-Site cluster.
• All sites must have the same number of storage systems. Storage systems must be added to
or removed from Multi-Site clusters equally.
Designing a Multi-Site SAN
The Multi-Site SAN software offers multiple features and the design flexibility to protect against
certain types of failures in the environment.
Data replication, site design, and quorum managers combine to protect against certain types of
failures in the environment. Some of the common types of failures a Multi-Site SAN protects against
include data center failures and storage system failures:
4 Designing a Multi-Site SAN