Detailed configuration of LVM under Linux

LVM is short for Logical Volume Manager, which provides a higher level of disk storage management for hosts. LVM helps system administrators easily allocate storage space for applications and users. Logical volumes under LVM management can be resized or added as needed. In addition, LVM can provide customized naming identifiers for managed logical volumes. Therefore, the use of LVM is mainly to facilitate the management of the storage system, increasing the scalability of the system.

First, prepare lvm environment

1. Hard disk preparation

Added a hard disk /dev/hdb.

Prepared three partitions, scheme As follows: The capacity is 100M, which is only for experimental preparation.

/dev/hdb1

/dev/hdb2

/dev/hdb3

2. Convert partition type to lvm volume

Fdisk /dev/hdb

t to lvm volume type

Device Boot Start End Blocks Id System

/dev/hdb1 1 208 98248+ 8e Linux LVM

/dev/hdb2 209 416 98280 8e Linux LVM

/dev/hdb3 417 624 98280 8e Linux LVM

Then w save and

#partprobe /* Disk partitioning is effective*/

Second, lvm creation process

1. Create physical volumes (PV) from the hard drive partition.

2.Creating volume groups (VGs) from physical volumes

3.Creating logical volumes (LVs) from volume groups and dispatching logical volume mount points , where only logical volumes can write data.

The biggest feature of lvm is that it can dynamically adjust the size of the partition, and can increase the capacity of the disk space as the partition capacity increases.

LVM Configuration and Creation

Third, LVM Physical Volume PV

1. Related Commands

pvcreate Create PV

pvscan Scan PV

pvdisplay Display PV

pvremove Delete PV

partprobe

2.Create a physical volume

If the above capacity is not enough, you can Add another partition to the physical volume.

[root@redhat ~]# pvcreate /dev/hdb1 /dev/hdb2

Physical volume "/dev/hdb1″ successfully created

Physical volume "/Dev/hdb2″ successfully created

[root@redhat ~]# pvscan

PV /dev/hdb1 lvm2 [95.95 MB]

PV /dev/hdb2 lvm2 [95.98 MB]

Total: 2 [191.92 MB] /in use: 0 [0 ] /in no VG: 2 [191.92 MB]

[root@redhat ~]# pvdisplay

- NEW Physical volume -

PV Name /dev/hdb1

VG Name

PV Size 95.95 MB

Allocatable NO

PE Size (KByte) 0

Total PE 0

Free PE 0

Allocated PE 0

PV UUID 2Ni0Tx-oeSy-zGUP-t7KG -Fh22-0BUi-iyPhhQ

- NEW Physical volume -

PV Name /dev/hdb2

VG Name

PV Size 95.98 MB

Allocatable NO

PE Size (KByte) 0

Total PE 0

Free PE 0

Allocated PE 0

PV UUID 2XLXfY-V3L2-Mtsl-79U4-ovuJ-YaQf-YV9qHs

Fourth, create LVM volume group VG

1. Related commands

vgcreate Create VG

vgscan Scan VG

vgdispaly

vgextend

vgreduce

vgchange

Vgremove

2.Create logical volume VG

[root@redhat ~]# vgcreate vg0 /dev/hdb1 /dev/hdb2

Volume group "vg0″

[root@redhat ~]# vgscan

Reading all physical volumes. This may take a while…

Found volume group "vg0″ using metadata type lvm2

[root@redhat ~]# vgdisplay

- Volume group -

VG Name vg0

System ID

Format lvm2

Metadata Areas 2

Metadata Sequence No 1

VG Access read/write

VG Status resizable

MAX LV 0

Cur LV 0

Open L V 0

Max PV 0

Cur PV 2

Act PV 2

VG Size 184.00 MB

PE Size 4.00 MB /*The size of the allocated block defaults to 4M*/

Total PE 46

Alloc PE /Size 0 /0

Free PE /Size 46 /184.00 MB

VG UUID kL5CGk-5Odk-r3PK-9q0A-s94h-OHv4-BojBnH Method to increase VG capacity to 1TB:

vgcreate -s 16M vg0 /dev/hdb1 /dev/hdb2

3. Delete and add logical volumes

[root@redhat ~]# vgreduce vg0 /dev/hdb2

Removed "/dev/hdb2″ from volume group "vg0″

[root@redhat ~]# vgextend vg0 /dev/hdb2

Volume group "vg0″ verified extended

V. Creating LVM logical volume LV

1. Related Commands

lvcreate

lvscan

lvdisplay

lvextend

lvreduce

lvremove

lvresize

2.Create a logical volume LV

[root@redhat ~]# lvcreate -L 184M -n data vg0

Logical volume "data" created

[root@redhat ~]# lvscan

ACTIVE '/dev/vg0/data' [184.00 MB ] inherit

[root@redhat ~]# lvdisplay

- Logical volume -

LV Name /dev/vg0/data

VG Name vg0< Br>

LV UUID HNKO5d-yRre-qVnP-ZT8D-fXir-XTeM-r6WjDX

LV Write Access read/write

LV Status available

# open 0

LV Size 184.00 MB

Current LE 46

Segments 2

Allocation inherit

Read ahead sectors 0

Block device 253:0

VI. Logical Volume LV Mounting LVM

Formatting of lv:

mkfs.ext3 /dev/vg0/data

mdkir /mnt/lvm

mount /dev/vg0/data /mnt/lvm

[root@redhat ~]# ls /mnt/lvm

lost +found

[root@redhat ~]# df -T

File System Type 1K-Blocks Available Available % Mounted Points

/Dev/hda3 ext3 7625092 2219460 5012040 31% /

/dev/hda1 ext3 101086 10006 85861 11% /boot

tmpfs tmpfs 150108 0 150108 0% /dev/shm

/dev/mapper/vg0-data

ext3 182469 5664 167385 4% /mnt/lvm

VII, LVM capacity adjustment

LVM capacity adjustment can be more The links are adjusted, for example, the capacity can be expanded on the physical volume, VG, and LV, which is one of the advantages of LVM.