topic Setting Target ID for LUNs in MSA Storage

Setting Target ID for LUNs

Andrew Carson — Mon, 16 Apr 2007 22:37:08 GMT

I've had a look through the forum but couldn't find anything along these lines, so forgive me if this is a previously asked & answered question. Have a blade center with FC2142 HBAs and ESX installed. Does anyone know how to set the TargetID for LUNs presented from a SAN?
TIA.

Re: Setting Target ID for LUNs

Uwe Zessin — Tue, 17 Apr 2007 00:38:13 GMT

You can't do that on a storage array. The target ID (if we are talking about the same thing: vmhbaA:T:L, where T is the target ID) is usually implicitly defined by the SAN topology.

For ESX V2.5 you can use "persistent target binding".

For ESX V3, you can't and don't need to, because it uses some form of "persistent LUN binding". I wrote 'some form', because you need to resignature the VMFS if you later re-map the storage space to a different LUN address.

Re: Setting Target ID for LUNs

Stephen Kebbell — Tue, 17 Apr 2007 01:02:44 GMT

Hi,

if you mean the Host LUN ID (the L that Uwe mentions from vmhbaA:T:L), you set that on the storage array. For an EVA LUN you can set it when you present the Virtual Disk. Why do you need to set a specifc LUN ID?

Regards,
Stephen

Re: Setting Target ID for LUNs

Uwe Zessin — Tue, 17 Apr 2007 01:09:07 GMT

> Why do you need to set a specifc LUN ID?

All VMware ESX V3 servers that access a single VMFS need to see it at the same LUN address.

If you add a server later to share this VMFS, you need to make sure it sees the virtual disk at the same LUN address.

Re: Setting Target ID for LUNs

Andrew Carson — Tue, 17 Apr 2007 02:31:31 GMT

Thanks for the replies, fellas. Yes - it was TargetID (TID) and not host LUn that I was after. I'm not sure if this helps yet - I'll have to pass the information on.