Linux Logical Volume Manager

["Matthew O'Keefe" <okeefe@styx.borg.umn.edu>]

       ********  Special Computer Engineering Seminar  ***********

                January 18th, 2000 from 7:00pm-9:00pm
            Amundson Hall (Chemical Engineering), Room B 75
                       University of Minnesota
                       Minneapolis, Minnesota
                     (here's a map to Amundson: 
              http://onestop.umn.edu/Maps/AmundH/index.html)

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               LVM - a Logical Volume Manager for Linux
                      Past, Present and Future

                           Heinz Mauelshagen (Linux LVM author)
                                T-Nova
                           Darmstadt, Germany

A Logical Volume Manager (LVM) is a subsystem for on-line disk storage
management which has become a de-facto standard accross UNIX implementations
and is a serious enabler for Linux in the Enterprise Computing area.

It 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 are divided into
fixed-sized sections, LVM allows the user to consider disks, also known as
physical volumes (PV), as a pool (or volume) of data storage,
consisting of equal-sized extents. 

A LVM system consists of arbitrary groups of physical volumes,
organized into volume groups (VG). 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 (think of it as a virtual disk consisting of one or
more physical disks). 

The pool of disk space that is represented by a volume group can be apportioned into virtual partitions, called logical volumes (LV) of various sizes.
A logical volume can span a number of physical volumes or represent only a
portion of one physical volume. The size of a logical volume is determined
by its number of extents. Once created, logical volumes can be used like
regular disk partitions - for eg. to create a file system or as a swap device. 

The talk includes the starting-points, objectives and basic 
conceptional issues of the LVM for Linux.
A demonstration of existing commands and usage szenarios follows.
A look into future features and extensions will finish the talk.

Mr. Mauelshagen's trip to the University of Minnesota is being 
sponsored by the Parallel Computer Systems Laboratory in the
Dept. of ECE. If you would talk to Heinz Mauelshagen during his 
stay in Minnesota, contact Matthew O'Keefe at 612-625-6306 or via
email at okeefe@ece.umn.edu.