ESX "raw" disk

Version 5


    A "raw" disk is a storage disk (if could be a physical disk, but usual is a LUN or a storage logical disk) that will be connect "directly" to the VM.

    Usually VM disks are vmdk files that reside on a VMFS volumes on a storage disk.

    In this case the raw disk is not formatted with VMFS but is formatted with guest OS filesystem.


    With ESX there are different way to have a "raw" disk:



    Raw disk pro and cons?

    VMFS vs RDM (vs VMDirectPath and other solutions)


    Extend a RDM disk

    RDM - unable to extend disk


    How to check if VM use RDM?

    A simple way is use RVTools.

    But also Perl or PowerShell scripts can be used:

    How to find the VM's connected to a partical RAW Map LUN.



    RDM on local disk

    With the VIC or the vSphere client is possible create a RDM disk for SAN's LUN.

    To use local storage with RDM (for example to connect and existing NTFS volume) the vmkfstools must be used from the CLI:

    Re: question about RDM using local disk ESX 4


    ESXi cannot use local disk RDM

    VMwareServer -> ESXi, Local Storage options? RDM?



    Virtual disk performance

    VMFS vs RDM (vs VMDirectPath and other solutions)

    Performance Characterization of VMFS and RDM Using a SAN -

    Thin vs Thick -