topic Re: 2 EVA Arrays -- Imperative to have diferent LUN Numbers? in Operating System - VMware

2 EVA Arrays -- Imperative to have diferent LUN Numbers?

Alzhy — Mon, 02 Aug 2010 13:24:36 GMT

Our Vmware Admin is saying LUN #s from differnt EVAs should be different. That if I already have a VDISK from EVA1 presented as LUN 1 - that I should NOT have a VDISK from EVA2 as still LUN1.

Is this true?

Re: 2 EVA Arrays -- Imperative to have diferent LUN Numbers?

Uwe Zessin — Mon, 02 Aug 2010 13:54:59 GMT

Technically, it is not necessary. Those LUNs are visible on different bus/targets addresses and they have different LUN WWNs, so they can be identified clearly.

But: if you even want to use Continuous Access on those virtual disks, I agree that it is a good idea to use unique LUN addresses (not sure if they had that in mind, though ;-)

Re: 2 EVA Arrays -- Imperative to have diferent LUN Numbers?

Steven Clementi — Tue, 03 Aug 2010 14:10:04 GMT

One of the things that I have started doing is setting a range of lun numbers to use per site. It is not necessary to have different lun numbers as mentioned, but for a quicker indentification of a lun... it might be worth doing.

I.E.

Site 1 EVA uses 1 through 100
Site 2 EVA uses 101 through 200

If I am doing CA with a vdisk, I make sure that I match the LUN numbers... site 1: LUN 22 (assuning this is the replicated vdisk), in Site 2 I'll use LUN 122 for the replicated copy of that vdisk.

This works well in a 2 site 2 EVA environment, but if you hame multiple arrays per site... you may end up having to use the same LUN numbers anyway.

I also have environments that use the same LUN numbers from multipe EVA's... so it is not "imperative" to use different numbers.

Steven