Converting iSCSI Targets in Windows to VMDK

Recently I was tasked with converting iSCSI connected disks on Windows Servers to a new SAN. With this migration it was decided that we should convert the disks to native ESXi VMDK format.

It is not possible to storage-vMotion the iSCSI disks without doing some work first (see below) as the hypervisor does not see the iSCSI disks as they are essentially remote disks.
In this article are some ideas you could potentially use to convert the iSCSI disks to VMDK.

Option A: Some downtime – easy

You could use the VMware vCenter Converter tool to migrate the disks to VMDK. This will involve some down time.

Option B: No down time necessary Рrequires some work


Another option which you could potentially do without any down time is to:

  • Attach a new HDD to the VM with the same size (or bigger) as the iSCSI disk
  • In disk management (diskmgmt.msc), right click the iSCSI volume and select mirror. Select the new HDD we just attached to the VM
  • Wait for the volumes to mirror – no down time required during the mirroring process. Depending on the volume size, the mirroring process could take a while.
  • When the mirroring process is complete, right click the iSCSI disk and select¬†Remove Mirror.¬†Select the iSSCI disk in the next window and confirm that you want to remove the mirror.
  • All your data that was previously on the iSCSI disk is now on the VMDK. You can safely disconnect the iSCSI volume.
  • Use vMotion to move the disks to a new server/storage appliance