Cisco AP776A - Nexus Converged Network Switch 5020 Configuration Manual page 531

Chapter 21 SAN Device Virtualization
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
If a storage array is replaced without using Cisco SDV, then it may require the following actions:
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More specifically, without SDV you might experience the following conditions:
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SDV enables you to achieve the following performance targets:
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Figure 21-4
When disk array X was deployed, the user created virtual devices for all the Fibre Channel interfaces
using SDV. After data replication from disk array X was completed, the user briefly pauses activity on
the application server and relinked disk array Y to the virtual devices used by the server, completing the
swapout of disk array X. No zoning changes or host operating system configuration changes were
required during the time-critical period when the swap was performed; this significantly minimized
application downtime.
The array administrator will likely have to perform actions on array Y for it to become a primary device
Note
and accept server logins before linking the virtual device to the array Y pWWN.
Figure 21-4
Server
OL-18084-01, Cisco MDS NX-OS Release 4.x
Taking down a server to modify zoning and account for the new array.
Changing the Cisco NX-OS configuration to accommodate Fibre Channel IDs (FC IDs) and
pWWNs of the new array.
Changing a server configuration to accommodate the new FC IDs and pWWNs.
It can take a considerable amount of time to configure a secondary device for a typical production
environment.
In the zoning configuration, all the initiators must be rezoned with the secondary device, and certain
initiators must also be reconfigured. For example, the WWN and FC ID of the secondary device are
different, so driver files must be changed and the server must be rebooted.
Clustering (multiple initiators) compounds the problem, and the failover procedure must be repeated
for each server of the cluster. Think of a server cluster as a set of HBAs–any storage array FC ID
changes must be performed for each HBA.
Reduce the amount of time it takes for data migration, and ultimately the overall amount of
downtime.
Easily scale to larger numbers of devices.
illustrates the benefits of SDV. In this configuration, disk array Y replaces disk array X.
SDV Example
Storage Arrays
X
Physical to Virtual Mapping
Virtual
Device
Y
Cisco MDS 9000 Family CLI Configuration Guide
About SDV
21-3