Levels; Level 1: Single Connectivity Fabric - HP StorageWorks 4000/6000/8000 - Enterprise Virtual Arrays Reference Manual

Hardware redundancy
NOTE:
For more information about high-availability configurations when using the HP B-series MP Routers
or C-series VSANs, see
Several factors affect SAN data availability:
Application software
Server operating systems
Server hardware
SAN fabric infrastructure
Primary and secondary storage
Number of switches
Number of ISLs
Number of paths between a server or clustered servers and the fabric
Number of storage controller paths in the fabric

Levels

This section describes the data availability levels.

Level 1: single connectivity fabric

Level 1 provides maximum connectivity but does not provide fabric resiliency or redundancy. Each
switch has one path to other switches in the fabric
one path to the fabric.
Figure 12 Level 1: single connectivity fabric
.
Level 2: single resilient fabric
Level 2 provides fabric path redundancy by using multiple ISLs between switches
server and storage system has one path to the fabric. If an ISL or switch port failure occurs, the switch
automatically reroutes data through an alternate fabric path and there is no interruption in server I/O
activity.
54 SAN fabric topologies
"High-availability MP Router
(Figure
25098a
configurations" on page 74.
12). Each server and storage system has
(Figure 13). Each