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• 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 LV
over several PVs. If these PVs 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
http://tldp.org/
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.
15.2.2 LVM Configuration with YaST
The YaST LVM configuration can be reached from the YaST Expert Partitioner (see
Section 15.1, “Using the YaST Partitioner” (page 227)) below Volume Management.
The Expert Partitioner allows you to edit and delete existing partitions and also create
new ones that should be used with LVM. The first task is to create PVs that provide
space to a volume group:
1 Select a hard disk from Hard Disks.
2 Change to the Partitions tab.
3 Click Add and enter the desired size of the PV on this disk.
Advanced Disk Setup 237