Logical Volume Management
From wiki.sixohthree.com
Logical Volume Management (LVM) is a storage mechanism for Linux that allows for dynamically resizing virtual partitions ("logical volumes," or LVs). This is done by breaking partitions or entire drives down into physical extents, then dynamically allocating these PEs into logical extents. These PEs can be assigned to any LV in the volume group.
[edit] Glossary
- volume group
- A collection of physical volumes and logical volumes.
- physical volume
- Hard drives/partitions in the VG.
- logical volume
- A breakdown of the VG into groups of blocks.
If a volume group is imagined as a single hard drive, the logical volumes are the partitions. Chunks of the VG can be left unallocated, with the free space available for addition to any LV in the VG.
[edit] FAQ
- Q. What happens if I buy a new IDE controller card and move hdb to hde?
- A. Each physical volume (be it a partition or a drive) is imprinted with a unique ID (UUID). Drives can be moved between controllers or even protocols (ie. ATA to SATA) with no reconfiguration necessary.
- Q. I've read that there's a LV size limitation of 255.99 GB. Isn't that sort of small?
- A. LVs are limited to 2^16^ PE, so if your physical extents are 4MB large, your logical volumes are limited to 4MB * 2^16^, or 256GB. A PE of 32MB means that a single volume is limited to 2TB.
