The Xen Storage Manager Volume driver (xensm) is a XenAPI hypervisor specific volume driver, and can be used to provide basic storage functionality, including volume creation and destruction, on a number of different storage back-ends. It also enables the capability of using more sophisticated storage back-ends for operations like cloning/snapshots, etc. The list below shows some of the storage plugins already supported in Citrix XenServer and Xen Cloud Platform (XCP):
NFS VHD: Storage repository (SR) plugin which stores disks as Virtual Hard Disk (VHD) files on a remote Network File System (NFS).
Local VHD on LVM: SR plugin which represents disks as VHD disks on Logical Volumes (LVM) within a locally-attached Volume Group.
HBA LUN-per-VDI driver: SR plugin which represents Logical Units (LUs) as Virtual Disk Images (VDIs) sourced by host bus adapters (HBAs). E.g. hardware-based iSCSI or FC support.
NetApp: SR driver for mapping of LUNs to VDIs on a NETAPP server, providing use of fast snapshot and clone features on the filer.
LVHD over FC: SR plugin which represents disks as VHDs on Logical Volumes within a Volume Group created on an HBA LUN. E.g. hardware-based iSCSI or FC support.
iSCSI: Base ISCSI SR driver, provides a LUN-per-VDI. Does not support creation of VDIs but accesses existing LUNs on a target.
LVHD over iSCSI: SR plugin which represents disks as Logical Volumes within a Volume Group created on an iSCSI LUN.
EqualLogic: SR driver for mapping of LUNs to VDIs on a EQUALLOGIC array group, providing use of fast snapshot and clone features on the array.
