Creating Lvm Partitions; Creating Volume Groups; Section 4.2, "Creating Lvm Partitions; Section 4.3, "Creating Volume Groups - Novell LINUX ENTERPRISE SERVER 11 - STORAGE ADMINISTRATION GUIDE 2-23-2010 Administration Manual

Figure 4-1
one single disk has been divided into three physical partitions (PART), each with a mount point
(MP) assigned so that the operating system can access them. On the right side, two disks have been
divided into two and three physical partitions each. Two LVM volume groups (VG 1 and VG 2)
have been defined. VG 1 contains two partitions from DISK 1 and one from DISK 2. VG 2 contains
the remaining two partitions from DISK 2. In LVM, the physical disk partitions that are incorporated
in a volume group are called physical volumes (PVs). Within the volume groups, four logical
volumes (LV 1 through LV 4) have been defined, which can be used by the operating system via the
associated mount points. The border 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
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 especially useful. It allows 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
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 version 2. Therefore, when talking about LVM, this section
always refers to LVM version 2.

4.2 Creating LVM Partitions

You create an LVM partition by first clicking Create > Do not format then selecting 0x8E Linux
LVM as the partition identifier. After creating all the partitions to use with LVM, click LVM to start
the LVM configuration.

4.3 Creating Volume Groups

If no volume group exists on your system yet, you are prompted to add one (see
possible to create additional groups with Add group, but usually one single volume group is
sufficient.
Enterprise Server system files are located. The physical extent size defines the size of a physical
block in the volume group. All the disk space in a volume group is handled in chunks of this size.
28 SLES 11: Storage Administration Guide
compares physical partitioning (left) with LVM segmentation (right). On the left side,
is suggested as a name for the volume group in which the SUSE
system
) can be enlarged when the free
/usr
LVM HOWTO (http://tldp.org/HOWTO/LVM-
Figure 4-2). It is
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Linux