Linux storage of lvm (Logical Volume Manager) Logical Volume Manager (1)

First we need to understand why with LVM

Generally expand partition：Need to be adjacent。

advantage：LVM makes it easier to manage disk space。If the file system needs more space，Available space volume groups which may be assigned to a logical volume，And you can adjust the size of the file system。If a disk error began to appear，You may be replaced by a disk volume group registered as physical volumes，And the logical volume range can be migrated to a new disk。

In a nutshell：LVM biggest benefit is，Increased easily reduce the partition。But we can not guarantee the security of data。

Lvm most significant feature is that between the file system and the hardware (physical disk) to add a level，A retractable partition。

one、LVM Components

Physical Disk：A partition、Full Disk 、RAID、SAN；The effect of physical volume is;

Physical Volume：physical volume(PV)。LVM The base used "physical" memory。This is usuallyIt is a block device，For example, a partition、Full Disk 、RAID、SAN；These are just ordinary physical partitionPartition，It must be initialized LVM Physical Volume，Can truly LVM use;

Volume Group：volume group(VG)。By one or more physical volumes of。Storage Pool。Default matterProcessing block is 4M。Specifies the physical block physical extent(ON)。on ON，To be investigated man vgcreate；

Logical Volume：logical volume(LV)。The last logical block group。Like the ordinary partition，You can format，Use the mount。It is a partition。But are free to expand the narrowing。

To show their relationship through a map

Ext3 —-> LV ——–> VG ——-> PV ——->Physical Disk

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two、Common management tools

Here are some common management tools：

The graphical management interface is very simple to save time to do this is not explained in detail

View version lvm

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First, by fdiskPartitioning，Here I separation of the four partitions aresda5，sda6，sda7，sda8The four partitions，Below we will complete the partitions of a physical disk to be initialized topvThat isLVM The base used "physical" memory

The partition is initialized to the physical volume group pv

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