The Device Mapper

• The Device Mapper driver provides a generic way of creating Mapped Devices, which may be used as Logical Volumes.

• It has no concept of Volume Groups.

• It does not know about metadata formats. Applications should manage metadata independently – in kernel- or user-space – and use the Device Mapper API to set up the virtual device.

• The core driver is small.

• The userland interface is via ioctl(). A filesystem interface (dmfs) is possible.