McDATA Sphereon 4300 Specifications download pdf (Page 242)

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McDATA Products in a SAN Environment - Planning Manual

Physical Planning Considerations

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

Full volatility is a feature (available on directors and fabric switches

with E/OSc 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.

When a director or fabric switch (without the full volatility feature

installed) powers off or fails, a dump file is written to non-volatile

random-access memory (NV-RAM). This dump file retains the last 30

Fibre Channel frames transmitted from the embedded port and the

last four frames transmitted to the embedded port.

These Fibre Channel frames are then written to diskette and included

as part of the data collection procedure. This process constitutes a

security breach if the frame data includes classified information.

With the full volatility feature installed and enabled, no frame data is

stored and the NV-RAM dump does not occur when the director or

switch powers off or fails. Although this feature limits the diagnostic

information available for fault isolation and resolution, the majority

of failures are resolved without the dump file.

Full Fabric

The Sphereon 4300 Fabric Switch is delivered without E_Port (ISL)

functionality and with all ports set to a BB_Credit value of 5. With the

full fabric feature installed and enabled, switch E_Port functionality

is provided and all port BB_Credit values are increased to 12. This

feature is provided only for the Sphereon 4300 Fabric Switch.

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McDATA Sphereon 4300 Specifications Page 242