Understanding and Designing Serviceguard Disaster Recovery Architectures

number of transactions you process, the more bandwidth and low latency you will need. The
bandwidth provided by the following connection types vary:
◦ T1 and T3: low end
◦ ISDN and DSL: medium bandwidth
◦ ATM: high end
• Reliability is affected regardless of whether data replication is performed, and therefore the
consistency of the data is also affected when you need to fail over to the recovery cluster.
Redundant leased lines should be used, and should be from two different common carriers,
if possible.
• Cost influences both bandwidth and reliability. Higher bandwidth and dual leased lines cost
more. Install redundant lines to address data consistency issues, weigh the price of data
currency, and then select the line speed accordingly.
Cross-subnet configuration
HP recommends that you use distributed neworks such that each site in a data center is on a
separate subnet. This helps in easier management of the networks along with protection from
broadcast storms and network-based attacks.
Figure 8 Two Data Centers on different subnets
Node A Node B Node C Node D
Data Center 1 Data Center 2
Network Switch
Network SwitchNetwork Switch
Network Switch
Router Router Router Router
WAN
Disaster Recovery Architecture Guidelines 17