Virtualization Pro Tips Blog

Video Training Tiplet: Connecting ESX 4.1 to iSCSI Storage in vCenter Server

I’ve always been a big fan of network storage over traditional Ethernet.  With iSCSI’s long history and the new technologies we’re seeing in Fibre Channel over Ethernet (FCoE), storage technologies are pretty obviously making a push towards using the copper infrastructure you already have.  If you haven’t made iSCSI connections yet in ESX 4.1, I’ll show you the steps to set up a simple one in this video.



Hey, this is Greg Shields with another Windows IT Pro Video Training Tiplet. Today, we’re connecting an ESX server version 4.1 to iSCSI storage inside vCenter Server.

Let’s say that you’ve completed the installation of your ESX server, and you’ve got some of the networking done but what you want to do is connect that ESX server to a little bit of shared storage where you’re going to put your virtual machines. We start that process here inside of the vSphere Client. Now let’s assume that we’ve already created a volume and exposed that LUN to this ESX server. You’ll see here

On this server we have two port groups and one physical adapter that are both connected in to the virtual switch. What we want to do is make a connection between this ESX server and that iSCSI storage. We start the process by going here under Add Networking and creating a VMkernel connection type. This connection type is used for things like vMotion, iSCSI, NFS, and even host management. In this case, because we’re doing iSCSI, this is the type of connection we want to create.

We have two options here, one for creating a virtual switch or one for using the existing virtual switch. In our case, we’re going to use that existing virtual switch. I choose the Next button, and I have the option of creating a network label, which I’ll just call iSCSI. This is just a friendly name for that port group. You’ll notice three options down here for whether we want to use that port group for vMotion, for Fault Tolerance, or for management traffic. Now because this is a storage connection, we don’t want to enable any of these features.

If you are actually pulling in VLANs into your ESX environment and you have them configured already on the network side, you may want to enter in a VLAN ID here as well. We’re going to choose None at this point.

If I choose the Next button, I need to provide the IP address settings for this connection. This will be a separate IP address than the one that’s used for that management network. I’ll choose for this with a 24-bit subnet mask. I have the VMkernel Default Gateway as, and I can change it by hitting the Edit button here.

If I click Next and Finish, that’ll actually go through the process of attaching that physical adapter to the switch and then ultimately to the iSCSI VMkernel port group. We’re only about half done at this point. Step two is to actually go and enable the iSCSI services. Let’s do that here under storage adapters. In this case, we’re going to use the iSCSI software adapter, because its already available on the server and it provides decent performance. If I choose the Properties button here, the first thing that I need to do is enable the software initiator. Once enabled, I have to point that software initiator to an iSCSI target. I’ll do so by using the Send Targets command to the particular host – the iSCSI server – that I want to connect to. In my case, it’ll be

If I choose OK, it’ll actually send the Send Targets command out to that iSCSI server. If the iSCSI server is responding, I should get some information here about that iSCSI server. I’m going to choose the Close button here, and you’ll notice that it tells me I have to do a rescan of the host bus adapter to complete the configuration change. What this rescan does is essentially make the volume available to me, and if I’ve done everything right on both the SAN side and the ESX side I should see the information show up down here under Details.

If I click, you’ll notice I have an iSCSI LUN here of type ROCKETDISK that’s connected to iSCSI LUN 0 and its got a capacity of about 300 gigs. What is means is that I have a successful connection between this ESX server and the iSCSI LUN.

We’re still not done yet. The last step is here under Storage. We have, at this point, created the connection to storage, but we don’t actually have a Datastore that actually up and created. What we want to do is click the Add Storage button here, and choose to create a new Disk/LUN. If I click Next, the available LUN should appear here inside the box at about 300 gigs in size. I choose the Next button. I can review the current disk layout. Next again. Enter a Datastore name. We’ll call this Datastore vm1.

And then lastly, how do I want to format the volume? You’ll notice that I have four different options here for how I want to configure that volume as I format it. Notice that there are four different options for block size ranging from 1 megabytes and 8 megabytes. Large files require a large block size, although the minimum size of a small file will be at least the block size. So if I have that’s a couple of K in size, and a block size that’s 8 megabytes, even though that file is a couple of K, it’ll actually consume 8 megabytes of disk space. On the other hand, if I create my block size as 8 megabytes, I can create my Datastore that is a full 2 terabytes in size. So, you’ll want to right-size how you want to set your block size by really how much space you intend to have for that volume.

In my case, I have a 300 gigabyte volume that I don’t plan on ever getting any larger than 300 gigabytes. So, I’ll set my block size to 2 megabytes. If you really don’t care, you can set your block size at 8 megabytes and ensure that you’ve always got plenty of space to grow.

I’ll set my capacity to maximize it, so that I’ll have the full space that I’ve assigned to that LUN. If I choose the Next button, and then Finish, it’ll actually complete the process of formatting that Datastore and making it available so that I can start installing virtual machines.

If you liked this Tip, come on back to Windows IT Pro, where we’ve got more Video Training Tiplets.


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