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How to extend Disk Space on a Server

A blog by Matthew Sharpe.

You sometimes need to extend your VM’s disk space – this can be done in a matter of minutes, with no server downtime, as long as you take the correct precautions e.g. snapshots.

The instructions below demonstrate the easiest and safest way to extend Disk Space on a Server for a Windows Server 2008 / R2 disk extension.

Firstly you have to identify the disk; this will be done on server manager on the relevant server. (Target server in this instance)

Extend diskspace on a server

You will then be presented with this box; here is where you will note down the SCSI ID and disk space for later. In this case it would be SCI ID: 6 Disk: 1

VMware virtual disk properties

Then go to the vSphere client within the Server you are on and check the available space which you can extend.

Here you will check the ‘Free’ space on the available disks to see if you can extend your server drives.

VMware resources

Now you’re going to check the SCSI ID and add the space.

VMware edit settings

Now before adding the space we will check that the SCSI ID and disk space matches, as you can see here it is 0:1 and 160GB.

VMware virtual disk

And here those stats matchup: 160GB and 0:1

virtual machine properties

After you have verified that it is the right disk, make the change and then press OK. I have added 1GB extra for this example.

Disk provisioning

Now the change has been made rescan the disk so that the new added space shows up in the server manager. Once the disks have rescanned you should have another section to your disk with an unallocated sign in the box.

Rescan disks

VMware disk

Now open command prompt as administrator

Administrator command prompt


Disk part

Now you can go make to server manager and verify that the disk has been extended.

When you verify that the disk extension has been carried out without any issues, you now can remove the snapshots from earlier on. To do this, follow these steps:

VMware snapshot

Volume extend

Now select the ‘Delete All’ option to delete all snapshots stored. And click yes to the confirmation box afterwards.


Finally wait for the process to complete and you have finished your volume extension.

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