Virtual machine snapshots will fail when ioTurbine caching software is installed and configured on the guest and host. This is because ioTurbine software creates and presents a RDM to the virtual machine as a caching device. This device is used by the ioTurbine filter drivers in the virtual machine to cache volume(s), disk(s) and/or file(s)

The ioSphere VM edition snapshot feature leverages the vSphere snapshot function and allows for easily taking snapshots of the VM configured for caching with ioTurbine. The ioTurbine snapshot will temporarily remove the RDM before the snapshot is taken. Therefore, before taking a snapshot of the VM, it is recommended to stop caching on all volumes, files and disks. Once caching is stopped, right click the VM under the Inventory pane on the left and select Take Snapshot from the dropdown menu. Follow the instructions in the window that appears.

For a detailed procedure, see the ioTurbine Administration Guide Appendix F, titled "Taking Snapshots with the MS GUI and CLI".