HP Cisco MDS 9020 - Fabric Switch Configuration Manual page 497

Chapter 20 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:
Taking down a server to modify zoning and account for the new array.
•
Changing the Cisco SAN-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.
•
More specifically, without SDV you might experience the following:
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 re-zoned 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.
SDV enables you to:
Reduce the amount of time it takes for data migration, and ultimately the overall amount of
•
downtime.
Easily scale to larger numbers of devices.
•
Figure 20-4
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 re-linked 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 log ins before linking the virtual device to the array Y pWWN.
Figure 20-4
Server
OL-16184-01, Cisco MDS SAN-OS Release 3.x
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
20-3