HP Surestore Disk Array FC60 HP SureStore E Disk Array FC60 Service Manual (A5 - Page 100

Non-High Availability Topologies Figure 36 through Figure 38 illustrate non-high availability topologies. These topologies do not achieve the highest level of data availability because they have a hardware component that represents a single point of failure. That is, if the critical component fails, access to the data on the disk array will be interrupted. These topologies are simpler and less expensive to implement than true high availability topologies. Characteristics • The critical components that represent a single point of failure in these configurations are: - The hub or switch. - The FC host adapter, if there is only a single connection from the host to the hub. In a cluster configuration a single host adapter does not represent a single point of failure because data will still be available through the other cluster host. - The FC cable if there is only a single connection between the host and the hub. In a cluster configuration the FC cable does not represent a single point of failure because data will still be available through the other cluster host. • The use of hubs and switches increases the distance that can be achieved between the host and the Disk Array FC60. The host and hub can be up to 500 meters apart, and the distance from the hub to the disk arrays can be an additional 500 meters. 100 Topologies for Windows NT and Windows 2000