Logical Volume Management (LVM) is a powerful and flexible system for managing disk storage in Linux. LVM allows for the creation of logical volumes (LVs) within volume groups (VGs), which are composed of physical volumes (PVs). In this article, we will explore the key concepts of LVM, including creating and managing PVs, VGs, and LVs.
Introduction to LVM
LVM provides a layer of abstraction between the physical storage devices and the file systems they contain. This allows for greater flexibility in managing storage, such as resizing volumes on the fly and migrating data between different physical devices without downtime.
At the core of LVM are the concepts of PVs, VGs, and LVs:
- Physical Volume (PV): A physical volume is a physical storage device, such as a hard drive or SSD, that is managed by LVM. PVs are divided into physical extents, which are the basic unit of allocation in LVM.
- Volume Group (VG): A volume group is a collection of one or more PVs that are combined into a single storage pool. VGs are divided into logical extents, which are mapped to physical extents on the PVs.
- Logical Volume (LV): A logical volume is a virtual partition that resides within a VG. LVs can be resized dynamically and can span multiple PVs within the same VG.
Creating PVs, VGs, and LVs
# Adding an Existing Partition to LVM
To add an existing partition to LVM, you first need to initialize the partition as a PV using the `pvcreate` command. For example, to add `/dev/sdb1` as a PV:
```bash
pvcreate /dev/sdb1
Next, you can create a new VG or add the PV to an existing VG using the `vgcreate` or `vgextend` command. For example, to create a new VG called `myvg` with `/dev/sdb1`:
```bash
vgcreate myvg /dev/sdb1
# Renaming a VG
If you need to rename a VG, you can use the `vgrename` command. For example, to rename `myvg` to `newvg`:
```bash
vgrename myvg newvg
# Displaying VG Information
To display information about a VG, you can use the `vgdisplay` command. This will show details such as the number of PVs, LVs, and the total size of the VG:
```bash
vgdisplay newvg
# Creating an LV within a VG
To create an LV within a VG, you can use the `lvcreate` command. Specify the size of the LV and the name of the VG where it should reside. For example, to create a 10GB LV called `mylv` in `newvg`:
```bash
lvcreate -L 10G -n mylv newvg
Managing PVs, VGs, and LVs
# Adding a PV to a VG
To add a new PV to an existing VG, you can use the `vgextend` command. For example, to add `/dev/sdc1` to `newvg`:
```bash
vgextend newvg /dev/sdc1
# Resizing an LV
If you need to resize an LV, you can use the `lvresize` command. For example, to increase the size of `mylv` by 5GB:
```bash
lvresize -L +5G /dev/newvg/mylv
current url：https://jgvyuw.e847z.com/bag/lvm-pv-vg-lv-69199