PVs are sliced into logical allocation units knows as physical extents (PEs) the default PE size is 4 MiB. Typically, the block device would be a physical disk, RAID volume, partition or even a file. LVM functions on top of Software-RAID solutions without issue, typically.Ĭoncept Physical volume A physical volume (PV) can be created using any block device you choose. In addition to combining drives into logical devices, you can also control the spread of data amongst devices through the use of striping, however this is often better left to a RAID implementation. Assuming your filesystem supports dynamic resizing, the upshot of this is you can grow/shrink logical drives (mount points) as you wish and distribute them over several partitions located on multiple physical drives. LVM allows one or more physical devices to be treated as a storage pool from which logical drives may be created whose size can altered dynamically. In 2003, a ground-up refactor of the original project was released under the GPL as LVM2 by Sistina Software (which was quickly acquired by Red Hat) and merged early the following year into the v2.6 Linux kernel. The v2.4 Linux kernel has the original LVM iteration adapted from the IBM code but with a command line syntax that imitates Hewlett Packard's LVM knock-off in that era's HP-UX. LVM is an abbreviation for Logical Volume Manager, a device mapper which has been available under Linux since 1997, when IBM released the source code to its Journaled File System (JFS) and Logical Volume Manager (LVM) from the AIX operating system under the name Enterprise Volume Management System (EVMS), to allow the open source community to determine the evolution of both.
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