The Layout Of A Logical Volume

• As we said, a logical volume is stored on a volume group.
• The logical volume is made of a list of physical extents (not necessarily contiguous) on the volume group.
• In addition, we might want to make the logical volume striped - that is, its data chunks will be stored alternately on different physical devices of the volume group. This may increase throughput.
• Thus, when we send I/O to a logical volume, it will may get mapped twice.
• This mapping is done in memory. If the device is very large - the map might be very large too...

Originally written by guy keren