Cisco Systems DSC9148D8G48PK9 manual FlexAttach Virtual pWWN CFS Distribution

Chapter 8 Configuring FlexAttach Virtual pWWN

Information About FlexAttach Virtual pWWN

•Replacement to the same port—A failed server can be replaced onto the same port without changing the SAN. The new server gets a same pWWN as the failed server because the virtual pWWN is assigned to the port.

•Replacement to (spare)—A spare server, which is on the same NPV device or a different NPV device) can be brought online without changes to the SAN. This action is achieved by moving the virtual port WWN from the current server port to the spare port.

•Server Mobility—A server can be moved to another port on the same NPV device or another NPV device without changing the SAN. This is accomplished by moving the virtual pWWN to the new port. No change is needed if FlexAttach was configured using the physical port WWN of the server to the virtual port WWN mapping.

Difference Between San Device Virtualization and FlexAttach Port Virtualization

Table 8-1describes the difference between SAN device virtualization (SDV) and FlexAttach port virtualization.

Table 8-1 Difference Between SDV and FlexAttach Virtualization

SAN Device Virtualization (SDV)	FlexAttach Virtualization
Facilitates target and disk management, and only	Facilitates server management and has no
facilitates disk and data migration.	restriction on the end devices used.
WWN NAT and Fibre Channel ID (FC-ID) are	WWN and Network Address Transport (NAT) is
allocated on the virtual device, both primary and	allocated to host bus adapter (HBA).
secondary.
FC-ID rewrite on the switch indicates a	No rewrite requirements.
rewrite-capable switch on the path.
Configuration is distributed. This allows	Configuration distribution is not required for any
programming rewrites and connectivity	of the interface-based configurations.
anywhere.
Configuration is secured to device alias.	Does not require device alias for virtual pWWN.
Does not allow automapping to the secondary	Allows automapping to the new HBA. Mapping
device.	process is manual for NPIV.

FlexAttach Virtual pWWN CFS Distribution

The FlexAttach virtual pWWN configuration is distributed for CFS through IPv4, and is enabled by default. The FlexAttach virtual pWWN distribution, by default, is on CFS region 201. The CFS region 201 links only to the NPV-enabled switches. Other CFS features such as syslog is on region 0. Region 0 will be linked through IPv4 for all NPV switches on the same physical fabric. If CFS has an option to link through IPv4 or ISL, then CFS will select the ISL path.

Note NPV switches do not have ISL (E or TE ports) and are linked through IPv4.

	Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide
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