Perform a Quasi Storage Snapshot on IOMEGA Storcenter

Jason has graciously asked if I would Guest Blog about a certain feature that I uncovered, while studying for my VCAP-DCA, with respect the IOMEGA Storcenter NAS devices.

In particular I was looking for a way to simulate the Snapshot and Resignaturing process that is on the VCAP-DCA Blueprint, Section 1.1 – Implement and Manage Complex Storage Solutions – Understand and apply VMFS Resignaturing.

I needed a way to simulate this in my homelab, but only had an IOMEGA Storcenter IX4-200d. While this device is certainly fine for most things, it is a little light on features that we would have in the Enterprise space. I knew this device utilized a purpose-built kernel based on Linux  and having been working with it for years I thought, why not poke around. The first thing that I noticed was that SSH was disabled by default. Fear not as there is a way around this. See my blog post: Howto Enable SSH Root Level Access on an IOMEGA Storcenter IX4-200d for instructions.

Step 1. Determine LUN to be Snapshot

In this example I have the following iSCSI Share mounted as the Original_Block Datastore in Virtual Center that I want to Snapshot or Replicate.Original_Block

Step 2. SSH into your Storcenter

If SSH is disabled you did not follow my instructions at the beginning of the post. Return to the beginning, and do not pass GO until you have performed that required step. For the rest of you, the Lifeline OS on the Storcenter creates a single file representation of the iSCSI Share. Change to that directory.

cd /mnt/soho_storage/iSCSI

Lets perform a directory list to see what files are in here.

List_of_iSCSI_Shares

This shows us that currently 2 iSCSI Shares exist. One is Test and the other is Test2. I know from my mount point in Virtual Center that the Share I am looking for is Test2.

Step 3. Create a Snapshot

Since there is no built-in Snapshot feature, we will simulate this functionality. We do this by copying the file to a new file, in *nix this is the cp command.Replicated_Share

As you can see, I now have my original Test2 file (which translates to a Test2 iSCSI Share), but I also now have a Test2Repl file. You guessed it, this is a new iSCSI Share which is a Snapshot of the original. There is one caveat; however; the Lifeline OS on the Storcenter does not know anything about this newly created iSCSI Share.

Step 4. Create new iSCSI Share

You will now need to log into the Storcenter Web Console in order to create that iSCSI Share from within the Lifeline OS. To do that, goto add shared storage -> iSCSI Drive and fill in the appropriate information as illustrated below.Setup_iSCSI_Share

Please note, that you MUST give the iSCSI Share that SAME NAME and SIZE that you defined in the previous cp command. Also if your environment requires it, check the Enable security checkbox.

When you click on apply, you will be given a summary screen showing what your share parameters are. Click Finish.

In Shared Storage, you will now see both iSCSI Shares.

Datastores

Step 5. Add LUN into Virtual Center

You will now be working in Virtual Center. You will need to Rescan All on the Storage Tab for your host. When completed, Add Storage and you will be presented with a screen similar to the following.Add_Copied_LUN

Select the copied LUN and click Next.

You will then be presented with the following screen. This is due to that fact that the LUN is a clone of the original, and as such contains the same unique identifier.Assign_New_Signature

We want to Assign a new signature, and click Next. The following page displays the summary of storage to add.

Assign_ConfirmationClick Finish.

You will now have the Original Datastore (Original_Block) and the Snapshot  Datastore (snap-***RANDOM***-Original_Block). This Datastore can be renamed if you desire.

Snapped_Datastore

Congratulations, you have now successfully created a Snapshot on an iSCSI Volume.

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