There is a very nice article about the aforementioned topic. The following URL provides the pages to the article, with some nice illustrations.
Here in part is some of the article text.
Introduction to LVM with RHEL, Fedora or Centos Linux
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This is the first part of an overview of Logical Volume Management. LVM was written originally by Heinz Mauelshagen in 1988. LVM has the advantages:
* Resizing of logical groups
* Resizing of logical volumes
* Snapshots from Read/Write volumes (in lvm2)
* Raid 0 of Logical Volumes. In this example i will create physical volumes (in /dev/sdb), a logical group and then a logical volume inside the logical group.
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The author is
University Student (Engineering), Sr. Unix Administrator, www.walterlamagna.com.ar