Creating easy to identify LeftHand Volumes on ESX/vSphere

Coming from mostly HP EVA environments I got used to identify a Volume/LUN by there LUN number which was a real unique identifier. I could always “talk” LUN number and be sure that it was understood and unique.
So ever since I’ve been working with our LeftHand environment I disliked the way that every Volume/LUN is marked with LUN 0.

Goal of this blog is to show you how you can easily rename a published LeftHand Volume to something that is easy to recognize and is unique.

As you can see in the image below the SCSI target number (T) seems to be the unique identifier  instead of the LUN number.
Well, fair enough you might, just switch to T number instead of the L number.  Unfortunately the SCSI target number can vary on the ESX hosts so it isn’t a static number that uniquely identifies a LUN!

x=SCSI Adapter Number
C= Controller
T= Target
L= LUN Number
P= Partition (if available)

The only real unique identifier in fact is a very long string, which can be compared to a WWN from FC devices.

So what’s there to dislike more? We are using many RDM’s and it takes a long time to identify the correct RDM with the LeftHand Volume.
First I needed to link either the “Identfier” or the “Target”-number to the actual target

Step 1: Select Paths and link the LeftHand volume name to the target number

Alternative to Step 1: Select Paths, right mouse-click the title bar, select Devices and link the LeftHand volume name to the Device which also contains the “Identifier” (this is a lot of scrolling work!)

Step 2: Go back to “Devices” and link the Target number to the “Identifier” (if you’ve done the alternative step above you already have the “Identifier” linked to the correct LeftHand volume)

Step 3: Add the new RDM to the VM and either identify the correct LeftHand volume by:
– Target number (if the VM is on the same ESX Host as where the ‘Target number to LeftHand volume’ is checked; Remember that the Target number isn’t a real unique identifier in the ESX Cluster!)
– The long Identify string.

Now this procedure could be easy when adding 1 RDM but in my case I had situations in where I needed to add 20 RDM’s in the same time so I needed to get a pen and paper and make an overview.
Lately (too late IMHO 😉 I discovered that the Volume Name can be renamed, making the new procedure as followes:

Step 1: Select Paths and link the LeftHand volume name to the target number

Step 2: Go back to Devices, select the correct Target number, right mouse click the entry and select rename. It’s advisable to keep the LeftHand volume name the same as the new VMware Name.

Step 3: Add the new RDM to the VM and easy identify now 😉

As a last remark I like to note that this “identify issue” doesn’t really occur while making new VMFS datastores.
Whenever walking through the wizard “Add Storage” the wizard ask you to select a Disk/LUN. Within this window (see image below) there’s a “Path ID”-property field in which you can directly see the LeftHand Volume name. This “Path ID”-property isn’t availabe in the wizard that lets you connect a RDM.

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