The benefits of logical volume management are more obvious on large systems with many disk drives.
Managing a large disk farm is a time-consuming job, made particularly complex if the system contains many disks of different sizes. Balancing the (often conflicting) storage requirements of various users can be a nightmare.
User groups can be allocated to volume groups and logical volumes and these can be grown as required. It is possible for the system administrator to "hold back" disk storage until it is required. It can then be added to the volume(user) group that has the most pressing need.
When new drive are added to the system, it is no longer necessary to move users files around to make the best use of the new storage; simply add the new disk into an exiting volume group or groups and extend the logical volumes as necessary.
It is also easy to take old drives out of service by moving the data from them onto newer drives - this can be done online, without disrupting user service.
To learn more about LVM, please take a look at the other papers available at Logical Volume Manager: Publications, Presentations and Papers .