VMware : Converting IDE disks to SCSI

After migrating the linux environment from KVM to ESX (see my previous post how to do it). We noticed that the disks
where connected as IDE disks, therefor it wasn’t possible to (dynamicly) resize them or add more disks then 4 IDE slots (including CD-ROM)

It pretty easy to convert these to a SCSI disk, but it will require downtime.
See also the VMware post about this:
Converting a virtual IDE disk to a virtual SCSI disk (1016192)

It’s recommendend for Windows machines to repair the MBR of the disk as adviced in the article above.
When encountering problems you could have a look at :
Repairing boot sector problems in Windows NT-based operating systems (1006556)

Luckily we tested it a few times in the Linux environment without encoutering problems (all VM’s are RedHat 6.4 or higher)

1) Turn off the VM
2) Locate the ESX host from the VM
3) Locate the datastores of the disks to edit
4) Turn on SSH on the ESX
5) Connect using SSH and go to the VM folder

# cd /vmfs/volumes/<datastore_name>/<vm_name>/


Now open the VMDK file using a VI editor like VI or nano for more information about VI/Nano
Editing files on an ESX host using vi or nano (1020302)
*Note: Nano is not available in ESXi. But can manually be installed

6) In this case we edit the TEST_PAT.vmdk file

# vi TEST_PAT.vmdk


When you look at the file you will see a ddb.adaptertype = “IDE” this is the value ESX uses to determine the adapter to use.In this case, when you add the VMDK using  “add new disk -> use existing disk” it will see IDE and add an IDE adapter.

So wee need to change this value

Specify one of these parameters: lsilogic or  buslogic .

This table shows the adapter type for the guest operating system:

Guest Operating System
Adapter Type
Windows 2003, 2008, Vista
Windows NT, 2000, XP

In this case we chose the lsilogic

Change IDE to LSILOGIC and save the file.

Next go back to your virtual machine and remove the disks you edited (don’t remove it from your storage), so wisely chose “Remove from Virtual Machine”
It’s important not to remove the disk first before you start editing because the VMDK descriptor file doesn’t exist yet if the disk is not connected to a VM.

Apply the settings. Now go back to edit settings -> add -> Harddisk -> Use an existing virtual disk -> Browse to the location of the disk file and click next a few times.
As you notice it will display Disk adapter as SCSI now.

Now you added your SCSI disk.

Thats it!

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