actually we figured out what was the problem. The problem was with SAN Zoning. In case of DUAL VIO Setup SAN Zoning has to be different.
Each switch should see both Servers
When using only one Fibre Channel per Virtual I/O Server, you need an
additional switch to have a highly available configuration. In this case, it is
important that the SAN zoning be configured such that the single Fibre Channel
in each Virtual I/O Server LPAR is zoned to see both storage controllers in the
FAStT. If a second Fibre Channel is used for additional redundancy, the storage
administrator must ensure that each Fibre Channel is zoned to only one of the
DS4200 controllers. Rules for attachment of FAStT storage units to AIX can be
found in the Storage Manager documentation of the Storage Manager products.
http://lh3.ggpht.com/_FOnSOMQiszQ/S3...dual_vio_1.JPG
http://lh6.ggpht.com/_FOnSOMQiszQ/S3...dual_vio_2.JPG
http://lh4.ggpht.com/_FOnSOMQiszQ/S3...dual_vio_3.JPG
SEE IBM REDBOOKS
PowerVM Virtualization on IBM System p: Introduction and Configuration Fourth Edition, SG24-7940-03
Redbooks, published 6 May 2008, last updated 11 January 2010,
IBM System p Advanced POWER Virtualization (PowerVM) Best Practices, REDP-4194-00
Redpapers, published 9 October 2006, last updated 22 May 2009, Rating: (based on 10 reviews)
83% 3. Advanced POWER Virtualization on IBM System p Virtual I/O Server Deployment Examples, REDP-4224-00
Redpapers, published 13 February 2007, last updated 19 June 2007, Rating: (based on 3 reviews)
& RED PAPER 4194