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Connecting VM Hosts to additonal SAN partition

Posted on 2014-11-25
Last Modified: 2014-12-08
I have a simple VMware infrastructure with 3 VM Hosts and 1 SAN at the back end. Hosts connect to SAN via SAS. I have a primary partition on the SAN that the hosts see/access and where all the VMs reside. Hosts run ESXi 5.5 (with latest updates) and my VMs are Win2012 R2.

I now want to create a second SAN partition and make it available to the Hosts/VMs. I created the partition and gave it a different LUN. However I cannot figure out how to have the hosts "see" it. I tried to create a new Datastore but there are no "available LUNs" to connect to. Am I doing something wrong? Could someone help?

Thanks! :-)
Question by:criskrit
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LVL 119
ID: 40465894
I assume if you click Add Storage it does not appear as a LUN?

Have you granted access Host ESXi Access to the new LUN, you have created ?

Author Comment

ID: 40465901
Correct, if I do "add Datastore" I don't see the LUN.

>> Have you granted Host ESXi Access to the new LUN --> No. How do I do this?
LVL 119
ID: 40465922
What is the SAS SAN?

How did you create and "map" the original first LUN0 ?
Netscaler Common Configuration How To guides

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Author Comment

ID: 40465931
The SAN is an HP MSA 2040 Dual controller, I am running two SAS cables from each host.

Not sure about the original LUN0, it's been a while but I think the ESXi environment detected this automatically.
LVL 119
ID: 40465939
You should be able to go to a Web GUI, and define the LUNs, and Access.

Page 61 of this document

shows the process, of provisioning, and Mapping the LUN


Author Comment

ID: 40465955
I have already created a separate volume with unique LUN 5. I thought this was sufficient and the hsots would be able to see it but no luck.

Is it possible that I need a separate SCSI/SAS adapter on the Host(s) with a separate physical connection to the SAN in order to see the second partition? Can I have many LUNs go through the same physical SAS cable connection?
LVL 119
ID: 40466317
Is LUN 5 setup the same as LUN x - vd01_v0000 ?

Author Comment

ID: 40468063
Yes, it is plain vanilla config for both partitions.

Back to the last question: Do I need a dedicated SAS link )controller-cable-controller) for each LUN? Or can I have many LUNs go through the same physical SAS connection?
LVL 119
ID: 40468132
Many LUNs should go through all SAS ports to multiple hosts.

otherwise you would not be able to use for clustering.

and HP use this MSA 2040 in their

HP Departmental Private Cloud Reference Architect design principles


This is about creating a Cluster for Hyper-V but, if you check pGaes 24/25, the LUN/Vdisk creation is the same as you are doing....

This is older model, MSA 2000.

Author Comment

ID: 40468249
Yep, this is how my volumes look...

I notice though that vol0 says type "standard" while vol1 says type "master volume". However I was never given an option to select this. Could it be a problem?

Accepted Solution

criskrit earned 0 total points
ID: 40478905
I connected with HP support and ended up with the simplest of solutions: Needed to reboot the ESXi host machines. After the reboot I could see the second LUN.
LVL 119
ID: 40478916
You have to do that every time, you Add a new LUN ?

That's not very practical ?

Author Comment

ID: 40478950
Yeah I know, sounds crazy. This is a new install so I just moved a coupe of VMs and restarted the hosts one by one. If it was a full-blown deployment it would have been a HUGE pain...
LVL 119
ID: 40478972
Thanks for sharing with the EE Community and coming back!

Author Closing Comment

ID: 40486401
Found the solution so I am sharing with the community.

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