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, and so on. Some of the storage plug-ins that are already supported in Citrix XenServer and Xen Cloud Platform (XCP) are:
NFS VHD: Storage repository (SR) plug-in that stores disks as Virtual Hard Disk (VHD) files on a remote Network File System (NFS).
Local VHD on LVM: SR plug-in that represents disks as VHD disks on Logical Volumes (LVM) within a locally-attached Volume Group.
HBA LUN-per-VDI driver: SR plug-in that represents Logical Units (LUs) as Virtual Disk Images (VDIs) sourced by host bus adapters (HBAs). For example, 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 plug-in that represents disks as VHDs on Logical Volumes within a Volume Group created on an HBA LUN. For example, 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 plug-in that 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.
