Increase the size of a volume on an EqualLogic PS4000XV SAN

You have a Windows 2008 R2 server that is nearly out of disk space on its ‘D’ drive. The ‘D’ drive is a volume on an EqualLogic PS4000XV Storage Area Network. This is a production server and the change needs to be done immediately in the middle of the day without service interruption. Whenever possible, I prefer to make changes like this outside of production hours or as scheduled downtime if you operate in a 24/7 environment since there is a chance that something could go wrong. When you have an issue like this that for whatever reason doesn’t get caught by your proactive monitoring systems and waiting will result in downtime anyway, the pros outweigh the cons of making a non-scheduled change (It may be a resume generating event otherwise).

Open the management console of your SAN and login as you normally would. If the volume you are going to expand is part of a “Volume Collection”, take a snapshot of the volume collection before beginning this process.

Locate the volume that needs to be expanded and select it. Verify you have the correct volume selected. Under “Activities” click “Modify volume settings”:

Click the “Space” Tab:

Enter the new size for the volume keeping in mind that a volume cannot be shrunk:

If you did not create a snapshot before beginning this process, click “Yes”. This will only create a snapshot of the volume that is being modified and not of all the volumes in the “Volume Collection” if it is part of one.

If you clicked yes in the previous step to create a snapshot, you will receive this dialog box. Enter a name for the snapshot and click “OK”:

The volume on the SAN has now been expanded. This doesn’t help your server though since it isn’t yet aware that there’s more space on the drive.

Login to the server that is connected to this volume and launch Computer Management. In the Storage>Disk Management section, you’ll notice the drive is still the same exact size as it was before and there is no free space that isn’t partitioned unless there was previously unpartitioned space.

Right click “Disk Management” and select “Refresh”:

The unpartioned free space will now show up on the drive, but hasn’t yet been added to the actual partition:

Right click the partition (‘D’ drive in the image below) and select “Extend Volume”:

Click “Next”:

Click “Next” to add all of the new free space to the ‘D’ partition:

Click “Finish”:

You now have the additional space in the ‘D’ partition and your operating system can actually use it:

This process was performed in the middle of the day on a production server with no downtime or interruption to service. In this example, an EqualLogic PS4000XV SAN with firmware v4.3.0 and Windows Server 2008 R2 Enterprise Edition were used. Your results may differ if this process is performed on another operating system or a SAN with a different firmware version.



  1. Rudolf

    I want to give thanks a lot for your work you have made in writing this blog post. I am hoping the same most effective work from you in the future as well.

  2. ITforMe

    Great post Mike. This will work well for those who have never had to do this before.

  3. facebook

    i love it

  4. kourtnie

    yeah nice

  5. Danny

    Great post. Quick question: I have a volume that houses my Virtualized servers operating systems. I want to expand the volume which thanks to your post seems fairly simple. Any red flags come to mind when increasing volume size when several OS are concerned?

    • µ

      Just for GP, I would shutdown the virtual guest OS’s before I started the process. I would also take a snapshot of the volume (at the SAN level) prior to increasing the size. Do the snapshot after shutting down the guest OS’s so the snapshot is application consistent and not crash consistent. If your using Hyper-V, I would also delete any snapshots created from within Hyper-V since they create AVHD files. Deleting the Hyper-V snapshots will merge the changes (AVHD files) back into the VHD files. If you have one volume and multiple vhd’s on it, once the volume is resized, you’ll need to expand the vhd’s if they’re fixed sized or dynamic and at their maximum size. I’ve used vmtoolkit to shrink vhd’s in the past and to turn fixed sized ones into dynamic ones, but not to increase their size. That shouldn’t be an issue to accomplish though.


  6. Alastair Turton

    Thanks Mike, ive never done this in a production environment before but it worked like a charm.. just have to upgrade the SAN firmware now!

  7. Diogo

    Nice post! but I have another situation, I have a file server that the D: drive is a volume that has 860Gb and I’m using RAW disk and the disk space is almost finishing whats the best way to add more space? I’ve seen some posts saying that a volume should have 500gb each one.. so should I create a new volume and join them on OS? Or can I use Vmware to make this join? My file server is using 2003 server R2. Thanks.

  8. Hugh

    Thank you. This affirmed the process that I was about to go through which is what I needed for peace of mind.

  9. John

    Worked Flawlessly with a PS6000 and a Windows 2008r2 server. Thank you for the reassurance, as I would have tried it anyhow. Easy as pie.

  10. Orion

    Thank you, this worked perfectly!

  11. Ruby

    Great post Mike, but i have Linux OS 🙁

  12. elderec

    Great post. Found it exactly when I needed it.

  13. Alex de Voor

    It does not work when using Raw Device Mapping, which extra steps do i have to make in Vcenter?


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