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Managing Storage Without a Dedicated Management Interface December 5, 2011

Posted by audiomatron in Uncategorized.

A conversation this past weekend with a colleague of mine (at my other job) who is new to Virtualization prompted me to write this.

Although virtualization is often touted as the most cost effective way to run your datacenter, the initial costs involved in rolling out a proper vSphere environment can actually be cost prohibitive. The largest part of that cost is, of course, storage. A SAN can be very expensive, and often after purchasing the servers, there is little left in the budget for proper storage. Sure, you can leverage local storage using a VSA like the vSphere storage virtual appliance, but to truly take advantage of all that virtualization has to offer, the best way to go is to find some way to obtain proper shared storage (plus, the vSphere storage appliance is expensive). There is no shortage of devices to fill this gap. A great many NAS boxes will do iSCSI. Boxes, such as the ones available from iOmega can be excellent alternatives to larger, enterprise class SANs, especially for the small business looking to virtualize.

In a proper virtual network design, you should keep storage traffic, such as iSCSI separate from the rest of your LAN. Still, you need a way to manage the storage device from the LAN. The larger SANs make this possible by providing dedicated management interfaces in addition to redundant interfaces for the actual storage traffic.  The problem with the smaller NAS solutions is that they usually only have one or two network interfaces. In the case of a NAS box with two network interfaces, you could dedicate one to storage traffic, connecting it to your storage network, and the other for management, connecting it to your LAN. However if you want redundancy in your storage network – using both interfaces for storage traffic, or if you just have one interface on your NAS, you will be left with no easy way to manage it. Sure, you could temporarily connect a laptop to your iSCSI switch, assign it an IP address in the same subnet as the NAS’s interface(s), and manage it that way, but that could be inconvenient sometimes – or even impossible if you aren’t physically in the datacenter where the storage is located. Not to fear, though. I have come up with a trick!

*Bear in mind this is from a small business perspective. I am assuming a physically separate storage network and no route from the LAN to it – no vLANs or anything of that nature.  In my own environment, I don’t have the proper equipment to do this (like a good fast router with multiple interfaces or a layer 3 switch), and neither do the few friends I’ve assisted with their virtualization initiatives.

In a typical virtual network design, you would probably have a vSwitch dedicated to storage (like iSCSI), with no port groups for VM traffic. The solution here is simple:

  1. Create a virtual machine port group in your storage vSwitch. Name it something recognizable – like “Storage Management”.
  2. Add a second virtual NIC to a VM of your choosing, and from the “Network Label” in the virtual NIC’s settings, choose your newly created network – in our case, it would be called “Storage Management”
  3. From within the VM, assign the newly created NIC a static IP address in the same subnet as the interface(s) on your NAS.
  4. Now, all you have to do to manage your NAS is to remote into this VM, and either install and run the NAS’s management tool (if it isn’t web based), or use the VMs web browser to management (if it is web based).

The only thing to bear in mind is that when you create new VMs or virtual NICs from now on, you will need to be careful to choose the right network to connect them to – whereas before there was probably only one choice.

As is my usual custom here, I must bow ask: DO you have any nifty tricks (or even a better way to do this) that can assist our small business brethren?




1. Imran Siddiqui - January 31, 2012


Another nice one! Now do you have put an article, best way to setup a home lab. You are most likely in the knowledge groove both as an expert and one who knows dummys like me, to put a nice piece for the benefits of virtual humanity.


audiomatron - February 1, 2012

Perhaps I will! I’ve been busy lately, so this blog has taken a back seat, so to speak. I am glad I can help! By the way, my name is Marcus – Fin is a French word which means “end”. I always like to put something goofy at the end of my posts…

Anyway, I’d love to document making a home lab, but I don’t have the money to buy gear. My buddy, Jase, has an excellent article about his home lab experience with several links to others. It can be found here http://www.jasemccarty.com/blog/?p=1516

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