Compaq 9900 - Manual (Page 93)

Hitachi Lightning 9900™ User and Reference Guide 79
4.5.3 Path Failover Support
The user should plan for path failover (alternate pathing) to ensure the highest data
availability. In the open-system environment, alternate pathing can be achieved by host
failover and/or I/O path failover software. The 9900 provides up to 32 fibre ports to
accommodate alternate pathing for host attachment. Figure 4.25 shows an example of
alternate pathing. The LUs can be mapped for access from multiple ports and/or multiple
target IDs. The number of connected hosts is limited only by the number of fibre-channel
ports installed and the requirement for alternate pathing within each host. If possible, the
alternate path(s) should be attached to different channel card(s) than the primary path.
The 9900 subsystem supports industry-standard I/O path failover products, including Hitachi
Dynamic Link Manager™, Sequent Multi Path, and VERITAS
® Volume Manager/DMP. For the
latest information on failover product releases, availability, and compatibility, please
contact your Hitachi Data Systems account team.
Fibre
Adapter
LU0
LU1
CHF0 CHF1 CHA0 CHA1
Failure
occurrence
Automatic path switching
Host switching
is not required. Capable of switching the path
LAN
Host A
(active)
Fibre
Adapter
Host B
(standby)
Fibre Fibre
9900 Subsystem
Fibre Cable
Figure 4.25 Alternate Pathing