Novell LINUX ENTERPRISE SERVER 10 SP2 - INSTALLATION AND ADMINISTRATION Installation Manual page 135

between different logical volumes need not be aligned with any partition border. See
the border between LV 1 and LV 2 in this example.
LVM features:
• Several hard disks or partitions can be combined in a large logical volume.
• Provided the configuration is suitable, an LV (such as /usr) can be enlarged when
the free space is exhausted.
• Using LVM, it is possible to add hard disks or LVs in a running system. However,
this requires hot-swappable hardware that is capable of such actions.
• It is possible to activate a "striping mode" that distributes the data stream of a logical
volume over several physical volumes. If these physical volumes reside on different
disks, this can improve the reading and writing performance just like RAID 0.
• The snapshot feature enables consistent backups (especially for servers) in the
running system.
With these features, using LVM already makes sense for heavily used home PCs or
small servers. If you have a growing data stock, as in the case of databases, music
archives, or user directories, LVM is just the right thing for you. This would allow file
systems that are larger than the physical hard disk. Another advantage of LVM is that
up to 256 LVs can be added. However, keep in mind that working with LVM is different
from working with conventional partitions. Instructions and further information about
configuring LVM is available in the official LVM HOWTO at
HOWTO/LVM-HOWTO/.
Starting from kernel version 2.6, LVM version 2 is available, which is downward-
compatible with the previous LVM and enables the continued management of old volume
groups. When creating new volume groups, decide whether to use the new format or
the downward-compatible version. LVM 2 does not require any kernel patches. It makes
use of the device mapper integrated in kernel 2.6. This kernel only supports LVM ver-
sion 2. Therefore, when talking about LVM, this section always refers to LVM version 2.
Instead of LVM 2, you can use EVMS (Enterprise Volume Management System),
which offers a uniform interface for logical volumes and RAID volumes. Like LVM 2,
EVMS makes use of the device mapper in kernel 2.6.
http://tldp.org/
Advanced Disk Setup 117