Full Volatility - McDATA StorageWorks 64 - SAN Director Switch Planning Manual

Physical Planning Considerations
5

Full Volatility

McDATA Products in a SAN Environment - Planning Manual
5-38
Server 1
Server 2
Server 3
OpenTrunking
Figure 5-8
The figure illustrates two Intrepid 6064 Directors connected by two
ISLs. Three servers use the ISLs to communicate with two storage
devices. Without trunking, servers 1 through 3 route Fibre Channel
traffic from to director B without regard to any data rates. A possible
scenario is that servers 1 and 2 route high data rate traffic through
ISL 1 to storage device 1 (ISL oversubscription) and server 3
routes low data rate traffic through ISL 2 to storage device 2
(ISL undersubscription).
Preferred path configurations are more restrictive than, and take
precedence over, OpenTrunking. Even if OpenTrunking is enabled,
no attempt is made to reroute traffic away from a preferred path,
even if the path is congested or BB_Credit starved.
Full volatility is a feature (available on directors and fabric switches
with E/OS Version 6.0 and later) that supports military, classified, or
other high-security environments that require Fibre Channel data not
be retained by the director or fabric switch after power off or failure.
Trunk
ISL 1
ISL 2
Director A
Storage 1
ISL 1
ISL 2
Director B
Storage 2