DUAL VIO'S CONCEPTS

Dual VIO  CONCEPT
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Why we need Dual VIO ?

For understanding the requirement of DUAL VIO, we need to go in flashback  and think about single vio concept......................

while doing so  few question arises in my mind.Let us take and example of small virtualized environment of 1 VIO and 4  VIO Client LPAR's and all disks are coming from VIO'S.

1.  How we will do the downtime maintenance activity of VIO.?
ans)  For  any downtime maintence actvity (upgrade etc) or in case of any issue which involves downtime of VIO, we need to bring down all 4 LPAR and then perform the activty on VIO.
     
2)  What if these 4 LPAR's are production critical and customer is not willing to afford the downtime?
ans) Here is the challenge  in doing the  VIO Downtime  related activities

3) Also what will happen if VIO server only automatically got rebooted or went down.?
ans)  This is also SPOF in case of virtualized single VIO implementation (where all the disks are coming from VIO)

For providing the solution to these issues , IBM introduced the DUAL VIO Concept , which provides solution for  all these drawbacks in simple virtualized environment .

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What is DUAL VIO Concept?

DUAL VIO concept provide the redundancy at VIO Server Level . It means that if 1 VIO Server is down  then the  network communication and the disks will be accessible through the second VIO.

HERE THE  QUESTION ARISES ?

How the commuication will happen through 2nd VIO? and the failover happens?
ans) while configuring DUAL VIO we also  need to implement SEA FAILOVER that if take care of network communication of the LPAR's.

HOw the disks will be accessible from 2nd VIO? and why?
ans) all the disks are mapped in cluster mode to both the VIO's from storage level ,I.e. the disk with same PVID is present on both VIO Servers and  VIOS mapping for the same disk  is done from both the VIO's .At  client level , you  will se two paths each coming from different vscsi.