Logical Volume Management (LVM) is a way of making logical volumes ("virtual partitions," if you like) out of parts of the disk. One of the options for partitioning at installation time is the LVM button at the bottom of the partitioning dialog, so you can create logical volumes when you install the system, or later if you wish.
The idea behind LVM is that a partitioning layout, once you have done it, is inflexible and hard to change. LVM provides some flexibility because it allows us to build partitions that actually span across physical disks or partitions.
The following is a brief overview of the concepts and basic commands of LVM2, which is the version shipped with modern versions of SUSE.
LVM operates at three levels:
■ Physical volumes: The raw disks or partitions that we are going to use
■ Volume Groups: Groups of physical volumes
■ Logical Volumes: The virtual partitions which we carve out of the volume groups
LVM is widely used in enterprise installations of Linux, and is actually the default installation option on Red Hat and Fedora systems.
As with partitioning more generally, you can create an LVM setup with the graphical YaST partitioning tool or with command line tools. Here is a brief summary of the command-line tools:
To make a partition into a physical volume for use with LVM, you should change its partition type to 8e (Linux LVM). This can be done using fdisk with the t (toggle partition type) command. You can also use an entire disk for a physical volume if you wish. For example:
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