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Best iSCSI config for ESXi 5.5 to HP MSA 2040 for failover and dual controller support

 
Aussie_Steve
Occasional Advisor

Best iSCSI config for ESXi 5.5 to HP MSA 2040 for failover and dual controller support

Gidday folks and thanks in advance for anyone with tips to offer.

I'm having "fun" trying to determine the best way to configure the iSCSI connections from a host server running ESXi 5.5U2  connected via dual DirectAttach cables to a dual controller HP MSA2040 SAN.

 

The SAN has 2 large vdisks running RAID10, each vdisk being a single datastore with one owned by Controller A (with B as a fallback) and the other owned by Controller B (with A as a fallback).

 

I have a pair of SFP+ ports on the server connected to the SAN using 10Gb DirectAttach cables with SFP+'s at each end and both the server and SAN seem to be happy with that arrangement. At the SAN end, one DA cable is connected to Port A-1 (first port on Controller A) and the other DA cable is connected to Port B-1 (first port on Controller B). The idea being datastoreA would usually be accessed via DAcableA on Port A-1 and datastoreB would usually be accessed via DAcableB on Port B-1 with either port being able to pick up control of a second vdisk/datastore if the other controller failed.

 

From what I can find online, VMware seems to favour NIC binding as a best practice for redundancy over multiple port iSCSI connections and so have a single NIC as the main iSCSI connection with the other NIC as a failover backup path for redundancy, but if I did that, it would mean whichever iSCSI connection was chosen as the active one, the controller connected to the standby one would not be accessible so one that controller's vdisk would failover to using the SAN's other disk controller for both vdisks killing the benefits of dual controllers sharing the workload.

 

How can I have ESXi 5.5U2 setup so that access to one datastore/vdisk is normally through one iSCSI port/cable and access to the other vdisk/datastore is normally through the other iSCSI port/cable with each one being the failover backup for the other?

 

I've never had to set-up a SAN in this fashion before so I'm very green to this. Any help or suggestions would be most appreciated. The HP best practices shows the host server cabled up with dual iSCSI cables with one in controller A and the other in Controller B but they don't show how to configure vSphere to make that work in practice. Also if we add a second server with the same setup except using the second port on each of the 2040 SAN controllers, are they setup the same way?

 

Thanks and remember some fairly plain English responses would be most appreciated. Apologies if I missed any typos!

1 REPLY 1
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gthomson
Occasional Visitor

Re: Best iSCSI config for ESXi 5.5 to HP MSA 2040 for failover and dual controller support

We're looking to do something similar I believe in the next month.

How did you end up going about it, and would you have done anything differently in hindsight?

Greg