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

Table 3 Alternative Multi-Site SAN configurations
DetailsDescriptionAlternate configuration
The Multi-Site SAN software supports running
many clusters in the same management
Multiple clusters running within the
same management group.
More than one Multi-Site cluster in
the management group
group. You simply need to make sure that
clusters have the same number of storage
systems in each site for that particular cluster.
A particular cluster can only span up to three
sites. However, the Multi-Site SAN software
There are more than three sites in
the cluster.
More than three sites
supports having more than one cluster. The
different clusters can span different sites
within the same cluster.
The Virtual Manager is used in two-site
configurations, and is not as commonly used
The Virtual Manager capability
remains in the product (a manual
process for recovering quorum).
Using Virtual Manager
as the Failover Manager. For more
information about the Virtual Manager, see
the chapter “Special Managers” in the HP
P4000 SAN Solution User Guide.
You can use Remote Copy to replicate data
from a Multi-Site SAN to a Disaster Recovery
The cluster contains Remote Copy,
which like all other SAN/iQ
Using Remote Copy with Multi-Site
SAN
or Backup site. See the chapterfeatures, is compatible with
Multi-Site SAN. “Understanding and Planning Remote Copy”
in the Remote Copy User Manual.
The Multi-Site SAN software can be used to
create clusters that span multiple networks
The Multi-Site SAN features can be
used to set up clusters that span
multiple subnets in the same site.
Multiple subnet clusters in the same
site
(subnets) in larger Enterprise data centers.
The storage systems all reside in the same
site. However, the cluster must be Multi-Site
if it is to contain storage systems from
different subnets.
Designing the network for the Multi-Site SAN
Good network design is a critical part of setting up a Multi-Site SAN that meets your needs. A
good Multi-Site SAN network encompasses the following attributes:
• Reliability
• High availability
• High performance
This section contains information about the minimum recommended network design considerations
when planning a network to support a Multi-Site SAN.
Best practices for implementing the Multi-Site SAN network
• Adequate bandwidth—Plan for 50 MB/sec of bandwidth for each storage system in each
site. For instance, if each site contains five storage systems, then you need 250 MB/sec
throughput. In this case, that translates into two Gigabit Ethernet links, or more.
• Low round-trip latency—In order to not impact disk I/O to the application server, the round-trip
latency between the sites must be no more than 2 ms.
• Redundant links—Have multiple physical connections (media) between the sites for redundancy.
The network should be configured so that a link failure does not cause the Multi-Site SAN to
go offline.
10 Designing a Multi-Site SAN