How to Convert a VMware Virtual IDE disk to SCSI disk

Why we need to convert Virtual IDE disk to SCSI disk

When converting a physical machine to a virtual machine using VMware Converter, if an adapter type is not selected during the initial customization the resulting virtual machine may contain an IDE disk as the primary OS disk. However, using IDE virtual disks have following limitations:

1. IDE disks are slower than SCSI disks in general.

2. It is not possible to increase the size of IDE virtual disks. Where as SCSI based virtual disk can be re-sized.

3. Veeam Backup and Replication software working in Virtual Appliance mode cannot backup IDE based virtual disks. 

4. With few guest operating systems, if the primary disk is an IDE virtual disk, the newly converted virtual machine may fail to boot because the guest OS does not support the driver. 

5. In ESX 4.x the default disk type for Windows XP 32bit virtual machine creation is IDE. This default value can be manually changed during the virtual machine creation wizard by selecting the custom option. However, Windows XP 64bit will still use SCSI by default.

6. Virtual machines may fail to boot with only a black screen after P2V conversion.

How  to convert Virtual IDE disk to SCSI disk

Now let's see how to convert the virtual disk from IDE to SCSI. Thankfully, there are various methods to convert the IDE virtual disk to SCSI, but the two prominent ways are: 

1. During P2V conversion of a virtul machine using VMware Converter.

2. Editing the virtual machine's VMDK disk geometry.

Below is the procedure to edit the virtual machine's VMDK disk geometry to convert a IDE virtual disk to SCSI.

1. SSH to the ESXi Host running the virtual machine.

2. Navigate to the virtual machine's home folder. e.g. cd /vmfs/volumes/<datastore_name>/<vm_name>/

3. Open the primary disk (.vmdk) using the vi editor. Note: In ESXi, there is no nano editor.

4. Find the parameter ddb.adapterType = "ide"

5. Change the adapter type to ddb.adapterType = "lsilogic" or ddb.adapterType = "buslogic" depending on the guest operating system support.

6. Save the file in vi edition by hitting ESC :wq keys.

7. Now from VMware vSphere Client:

• Click Edit Settings for the virtual machine.
• Select the IDE virtual disk.
• Choose to Remove from  virtual machine.
• Click OK.

Caution: Make sure that you do not choose Remove from virtual machine and delete files from Disk 

8. From the Edit Settings menu for this virtual machine:

• Click Add > Hard Disk > Use Existing Virtual Disk.
• Navigate to the location of the disk and select to add it into the virtual machine.
• Choose the same controller as in Step 3 as the adapter type. The SCSI ID should read SCSI 0:0.

Note: If a CDROM device exists in the virtual machine it may need to have the IDE channel adjusted from IDE 0:1 to IDE 0:0. If this option is greyed out, remove the CD-ROM from the virtual machine and add it back. This sets it to IDE 0:0.