7.2. What is LVM2?

LVM version 2, or LVM2, is the default for Red Hat Enterprise Linux, which uses the device mapper driver contained in the 2.6 kernel. LVM2, which is almost completely compatible with the earlier LVM1 version, can be upgraded from versions of Red Hat Enterprise Linux running the 2.4 kernel.
Although upgrading from LVM1 to LVM2 is usually seamless, refer to Section 7.3, “Additional Resources” for further details on more complex requirements and upgrading scenarios.