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In dem Vortrag wird Heinz Mauelshagen seine Implementierung eines Logical Volume Managers für Linux vorstellen.

 

Zur Thematik

The Logical Volume Manager (LVM) is a subsystem for on-line disk storage management. Originally developed by Veritas it has become a defacto standard for storage management. IBM and HP developed their own LVM implementation (which is different from the Veritas LVM product). The Linux implementation is similar to the HP implementation.

The Logical Volume Manager (LVM) adds an additional layer between the physical peripherals and the i/o interface in the kernel to get a logical view of disks. Unlike current partition schemes where disks were divided into fixed-sized sections, LVM allows the user to consider the disks, also known as physical volumes, as a pool (or volume) of data storage, consisting of equal-sized extents.

A LVM system consists of arbitrary groupings of physical volumes, organized into volume groups. A volume group can consist of one or more physical volumes. There can be more than one volume group in the system. Once created, the volume group, and not the disk, is the basic unit of data storage. Thus, whereas earlier one would move disks from one system to another, with LVM, one would move a volume group from one system to another. For this reason it is often convenient to have multiple volume groups on a system.

Volume groups can be subdivided into virtual disks, called logical volumes. A logical volume can span a number of physical volumes or represent only a portion of one physical volume. The pool of disk space that is represented by a volume group can be apportioned into logical volumes of various sizes. The size of a logical volume is determined by its number of extents. Once created, logical volumes can be treated just like disk partitions. Logical volumes can be assigned to file systems, used as swap or dump devices, or used for raw access.