Image mode creates one-to-one mapping of logical block addresses (LBAs) between a  volume and an MDisk (LU presented by the virtualized storage). Image mode volumes have  the minimum size of one block (512 bytes) and always occupy at least one extent. An Image  mode MDisk cannot be used as a quorum disk and no IBM Spectrum Virtualize system  metadata extents are allocated from it; however, all of the IBM Spectrum Virtualize copy  services functions can be applied to image mode disks. The difference between a managed  mode volume (with striped extent allocation) and an image mode volume is shown in  Figure 7-4. An image mode volume is mapped to one, and only one, image mode MDisks and is mapped  to the entirety of the MDisk. Therefore, the image mode volume capacity must be equal to the  size of the corresponding image mode MDisk. If the size of the (image mode) MDisk is not a  multiple of the MDisk group’s ex tent size, the last extent is marked as partial (not filled). When you create an image mode volume, the specified MDisk must be in unmanaged mode  and must not be a member of a storage pool. As the image mode volume is configured, the  MDisk is made a member of the specified storage pool ( Storage Pool_IMG_ xxx ). IBM Spectrum Virtualize also supports the reverse process, in which a managed mode  volume can be migrated to an image mode volume. The extent size that is chosen for this  specific storage pool must be the same as the extent size of the storage pool into which you  plan to migrate the data off the image mode volumes. If a volume is migrated to another  MDisk, it is represented as being in managed mode during the migration. Its mode changes to  “image” only after the process completes. It is a preferred practice to put image mode MDisks in a dedicated storage pool and use  a special name for it (for example,  Storage Pool_IMG_ xxx ).  Figure 7-4 Image mode volume versus striped volume 246  Implementing the IBM Storwize V7000 with IBM Spectrum Virtualize V8.2.1