LVM （逻辑卷管理器）

一个新的磁盘，如何去做LVM？

一、格式化磁盘

[root@localhost ~]# fdisk -l   #查看当前的设备有哪些

Disk /dev/sda: 21.4 GB, 21474836480 bytes

255 heads, 63 sectors/track, 2610 cylinders
……此处省略部分输出内容……

/dev/sda3             153        2610    19743885   83  Linux
Disk /dev/sdb: 42.9 GB, 42949672960 bytes

……此处省略部分输出内容……

Disk /dev/sdb doesn't contain a valid partition table

……此处省略部分输出内容……

Disk /dev/sdc doesn't contain a valid partition table

从格式化磁盘开始

[root@localhost ~]# fdisk /dev/sdb  ##对第二块磁盘进行分区

Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel

此处省………………略若干字

2) booting and partitioning software from other OSs

   (e.g., DOS FDISK, OS/2 FDISK)

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

Command (m for help): n    ##n表示new，建立新的分区

 p   primary partition (1-4)

p    ###代表主分区

Partition number (1-4): 1 ##主分区号

First cylinder (1-5221, default 1): 1##磁盘分区起始点

Last cylinder or +size or +sizeM or +sizeK (1-5221, default 5221): +10000M ##指定第一个分区大小为10G

Command (m for help): n #继续新建分区

Command action

   e   extended

   p   primary partition (1-4)

p   ##依旧是主分区

Partition number (1-4): 2  ##编号为2

First cylinder (1218-5221, default 1218): 

Using default value 1218 ##起始点直接回车表示默认

Last cylinder or +size or +sizeM or +sizeK (1218-5221, default 5221): +20000M  ###指定大小为20G

 

Command (m for help): n    ##新建分区

Command action

   e   extended

   p   primary partition (1-4)

p   ##选择主分区

Partition number (1-4): 3  ##主分区编号为3

First cylinder (3651-5221, default 3651): 

Using default value 3651   ###直接回车默认

Last cylinder or +size or +sizeM or +sizeK (3651-5221, default 5221): 

Using default value 5221  ####回车默认

Command (m for help): t   ###使用t表示转换分区类型

Partition number (1-4): 1  ###输入分区号

Hex code (type L to list codes): 8e  ###输入分区类型代码

Changed system type of partition 1 to 8e (Linux LVM)

Command (m for help): t

Partition number (1-4): 2

Hex code (type L to list codes): 8e

Changed system type of partition 2 to 8e (Linux LVM)

Command (m for help): t

Partition number (1-4): 3

Hex code (type L to list codes): 8e

Changed system type of partition 3 to 8e (Linux LVM)

Command (m for help): p  ###列出所有分区

Disk /dev/sdb: 42.9 GB, 42949672960 bytes

……

   Device Boot      Start         End      Blocks   Id  System

/dev/sdb1               1        1217     9775521   8e  Linux LVM

/dev/sdb2            1218        2434     9775552+  8e  Linux LVM

/dev/sdb3            2435        5221    22386577+  8e  Linux LVM

…………此处省略部分输出内容……

Command (m for help): w   ###保存退出

The partition table has been altered!

Calling ioctl() to re-read partition table.

Syncing disks.

[root@localhost ~]# partprobe  /dev/sdb  /dev/sdc

二、建立PV（物理卷）

[root@localhost ~]# pvcreate /dev/sdb1 /dev/sdb2 /dev/sdb3

  /dev/cdrom: open failed: Read-only file system

  Physical volume "/dev/sdb1" successfully created

  Attempt to close device '/dev/cdrom' which is not open.

  Physical volume "/dev/sdb3" successfully created

[root@localhost ~]# pvdisplay  ###展示物理卷 

  "/dev/sdb1" is a new physical volume of "9.32 GB"

  --- NEW Physical volume ---

  PV Name               /dev/sdb1

  VG Name               

  PV Size               9.32 GB

  ……此处省略……部分显示结果

  PV Size               21.35 GB

  Allocatable           NO

  …………

  PV UUID               rdfuEk-FUli-Iyks-sGrO-1bco-G7ND-NYyrjM

   三、建立VG卷组

[root@localhost ~]# vgcreate vg1 /dev/sdb1 /dev/sdb2 /dev/sdb3    ####建立名称为vg1的卷组

Volume group "vg1" successfully created

[root@localhost ~]# vgdisplay   ###列出卷组

  --- Volume group ---

  VG Name               vg1

  System ID             

  Format                lvm2

  Metadata Areas        3

  Metadata Sequence No  1

  VG Access             read/write

  ………………………………

  Free  PE / Size       10237 / 39.99 GB

  VG UUID               sgtFaV-Hd31-dCag-jPbq-50Ia-WOQa-Ccwo3x

四、建立LV逻辑卷

[root@localhost ~]# lvcreate -L 15000M -n lv1 vg1   ###创建名为lv1，大小为15G的逻辑卷

  /dev/cdrom: open failed: Read-only file system

  Logical volume "lv1" created

[root@localhost ~]# lvdisplay    ###展示逻辑卷

  --- Logical volume ---

  LV Name                /dev/vg1/lv1

  VG Name                vg1

  LV UUID                fPAVct-8lZ2-Nvs6-KK2n-IMqo-1enG-hHt2tN

  LV Write Access        read/write

  LV Status              available

  # open                 0

  LV Size                14.65 GB

  Current LE             3750

  Segments               1

  Allocation             inherit

  Read ahead sectors     auto

  - currently set to     256

  Block device           253:0

格式化LV1并挂载

[root@localhost ~]# mkfs.ext3 /dev/vg1/lv1    ###将lv1格式化成ext3格式

mke2fs 1.39 (29-May-2006)

Filesystem label=

OS type: Linux

Block size=4096 (log=2)

Fragment size=4096 (log=2)

1921984 inodes, 3840000 blocks

192000 blocks (5.00%) reserved for the super user

First data block=0

Maximum filesystem blocks=3934257152

118 block groups

32768 blocks per group, 32768 fragments per group

16288 inodes per group

Superblock backups stored on blocks: 

        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208

Writing inode tables: done                            

Creating journal (32768 blocks): done

Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 21 mounts or

180 days, whichever comes first.  Use tune2fs -c or -i to override.

[root@localhost ~]# mount /dev/vg1/lv1 /mnt/    ####将逻辑卷挂载到/mnt

[root@localhost ~]# mount  ###查看当前的挂在情况

/dev/sda3 on / type ext3 (rw)

proc on /proc type proc (rw)

sysfs on /sys type sysfs (rw)

devpts on /dev/pts type devpts (rw,gid=5,mode=620)

/dev/sda1 on /boot type ext3 (rw)

tmpfs on /dev/shm type tmpfs (rw)

none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)

sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
/dev/mapper/vg1-lv1 on /mnt type ext3 (rw)

扩大LV

[root@localhost ~]# df -Th    ####查看当前的分区挂载

Filesystem    Type    Size  Used Avail Use% Mounted on

/dev/sda3     ext3     19G  4.1G   14G  24% /

/dev/sda1     ext3    190M   12M  169M   7% /boot

tmpfs        tmpfs    125M     0  125M   0% /dev/shm

/dev/mapper/vg1-lv1

              ext3     15G  165M   14G   2% /mnt

Disk /dev/sdc: 42.9 GB, 42949672960 bytes

255 heads, 63 sectors/track, 5221 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System

/dev/sdc1               1         366     2939863+  8e  Linux LVM

[root@localhost ~]# vgdisplay #####查看卷组的状态

  --- Volume group ---

  VG Name               vg1

  System ID             

 ……

  Alloc PE / Size       3750 / 14.65 GB

  Free  PE / Size       6487 / 25.34 GB

  VG UUID               sgtFaV-Hd31-dCag-jPbq-50Ia-WOQa-Ccwo3x

[root@localhost ~]# vgextend vg1 /dev/sdc1  #####将/dev/sdc1扩到卷组vg1中

  /dev/cdrom: open failed: Read-only file system

  No physical volume label read from /dev/sdc1

  Physical volume "/dev/sdc1" successfully created

  Volume group "vg1" successfully extended

[root@localhost ~]# vgdisplay 

  --- Volume group ---

  VG Name               vg1

  System ID             

  Format                lvm2

  Metadata Areas        4

  Metadata Sequence No  3

  VG Access             read/write

  VG Status             resizable

  MAX LV                0

  Cur LV                1

  Open LV               1

  Max PV                0

  Cur PV                4

  Act PV                4

  VG Size               42.79 GB

  PE Size               4.00 MB

  Total PE              10954

  Alloc PE / Size       3750 / 14.65 GB

  Free  PE / Size       7204 / 28.14 GB

  VG UUID               sgtFaV-Hd31-dCag-jPbq-50Ia-WOQa-Ccwo3x

[root@localhost ~]# lvextend -L +2000M /dev/vg1/lv1   ####对lv进行扩容

  /dev/cdrom: open failed: Read-only file system

  Extending logical volume lv1 to 16.60 GB

  Logical volume lv1 successfully resized