LVM建立以及使用

           LVM(Logical VolumeManager 邏輯卷管理)

在磁盤分區和文件系統之間添加一個邏輯層，來爲文件系統屏蔽下層磁盤分區佈局，提供一個抽象的盤卷，在盤捲上創建文件系統，來提升磁盤分區管理的靈活性可實現零停機前提下自如對文件系統的大小進行調整，能夠方便實現文件系統跨越不一樣磁盤和分區。

下圖是我根據本身的理解畫出的一張圖。此圖背景是：公司有一臺戴爾R910服務器，如今接上6個SAS硬盤，作成raid5磁盤陣列，最後一個硬盤設爲全局熱備。而後在戴爾自帶的磁盤陣列管理上把剩下的5塊硬盤劃分爲4個VD(虛擬磁盤)，把系統所有安裝在第一個VD，而後剩下的3個VD利用LVM技術整合成一個大分區用於存儲數據。

下面分享的我建立LV的整個過程，此操做系統爲 Red hat enterprise linux 5.5 x86_64 : 

-------------------------------------  下面是對VD磁盤的分區管理  ----------------------------------------------------

 

[root@mail ~]# ls  /dev/sd* #查看當前系統有多少分區

/dev/sda /dev/sda1  /dev/sda2  /dev/sda3 /dev/sdb  /dev/sdc  /dev/sdd

 

[root@mail ~]# fdisk /dev/sdb  #對第二塊硬盤進行分區

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

Building a new DOS disklabel. Changes willremain in memory only,

until you decide to write them. After that,of course, the previous

content won't be recoverable.

 

 

The number of cylinders for this disk isset to 248029.

There is nothing wrong with that, but thisis larger than 1024,

and could in certain setups cause problemswith:

1) software that runs at boot time (e.g.,old versions of LILO)

2) booting and partitioning software fromother OSs

  (e.g., DOS FDISK, OS/2 FDISK)

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

 

Command (m for help): m  #列出全部幫助信息

Command action

  a   toggle a bootable flag

  b   edit bsd disklabel

  c   toggle the dos compatibilityflag

  d   delete a partition  #刪除分區

  l   list known partition types   #列出已知的分區類型

  m   print this menu

  n   add a new partition   #建立新分區

  o   create a new empty DOSpartition table

  p   print the partition table   #在屏幕打印出全部的分區

  q   quit without saving changes   #退出不保存

  s   create a new empty Sundisklabel

  t   change a partition's system id    #更改分區的系統ID

  u   change display/entry units

  v   verify the partition table

  w   write table to disk and exit    #把當前配置信息寫入硬盤並退出

  x   extra functionality (expertsonly)

 

Command (m for help): n   #建立新分區

Command action

  e   extended  #建立邏輯分區 [ 5,6,7…… ]

  p   primary partition (1-4)  #建立主分區[ 1,2,3,4 ]

p   #建立主分區

Partition number (1-4): 1  #建立第一塊主分區

First cylinder (1-248029, default 1):

Using default value 1

Last cylinder or +size or +sizeM or +sizeK(1-248029, default 248029):

Using default value 248029

 

Command (m for help): l  #列出已知的分區類型

 

 0 Empty           1e  Hidden W95 FAT1 80  Old Minix       bf Solaris       

 1 FAT12           24  NEC DOS         81 Minix / old Lin c1  DRDOS/sec(FAT-

 2  XENIXroot      39  Plan 9          82 Linux swap / So c4  DRDOS/sec(FAT-

 3  XENIXusr       3c  PartitionMagic  83 Linux           c6  DRDOS/sec (FAT-

 4  FAT16<32M      40  Venix 80286     84 OS/2 hidden C:  c7  Syrinx        

 5 Extended        41 PPC PReP Boot   85  Linux extended  da Non-FS data   

 6 FAT16           42  SFS             86 NTFS volume set db  CP/M / CTOS /.

 7 HPFS/NTFS       4d  QNX4.x          87 NTFS volume set de  DellUtility  

 8 AIX             4e  QNX4.x 2nd part 88  Linux plaintext df  BootIt        

 9  AIXbootable    4f  QNX4.x 3rd part  8e Linux LVM       e1  DOS access    

 a  OS/2Boot Manag 50  OnTrack DM      93 Amoeba          e3  DOS R/O       

 b  W95FAT32       51  OnTrack DM6 Aux 94  Amoeba BBT      e4 SpeedStor     

 c  W95FAT32 (LBA) 52  CP/M            9f BSD/OS          eb  BeOS fs       

 e  W95FAT16 (LBA) 53  OnTrack DM6 Aux a0  IBM Thinkpad hi ee  EFI GPT       

 f  W95Ext'd (LBA) 54  OnTrackDM6      a5 FreeBSD         ef  EFI (FAT-12/16/

10 OPUS            55  EZ-Drive        a6 OpenBSD         f0  Linux/PA-RISC b

11 Hidden FAT12    56  Golden Bow      a7 NeXTSTEP        f1  SpeedStor     

12 Compaq diagnost 5c  PriamEdisk     a8  Darwin UFS      f4 SpeedStor     

14 Hidden FAT16 <3 61 SpeedStor       a9  NetBSD          f2 DOS secondary 

16 Hidden FAT16    63  GNU HURD or Sys ab  Darwin boot     fb VMware VMFS   

17 Hidden HPFS/NTF 64  NovellNetware  b7  BSDI fs         fc VMware VMKCORE

18 AST SmartSleep  65  Novell Netware  b8 BSDI swap       fd  Linux raid auto

1b Hidden W95 FAT3 70  DiskSecureMult bb  Boot Wizard hid fe  LANstep       

1c Hidden W95 FAT3 75  PC/IX           be Solaris boot    ff  BBT           

 

 

Command (m for help): t  #更改分區的系統ID

Selected partition 1  #選擇第一個分區

Hex code (type L to list codes): 8e  #默認是linux格式，更改成Linux LVM

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

 

Command (m for help): p  #在屏幕打印出全部的分區

 

Disk /dev/sdb: 2040.1 GB, 2040109137920bytes

255 heads, 63 sectors/track, 248029cylinders

Units = cylinders of 16065 * 512 = 8225280bytes

 

  Device Boot        Start        End      Blocks      Id    System

/dev/sdb1               1         248029 1992292911   8e    LinuxLVM

 

 

Command (m for help): w #把當前配置信息寫入硬盤並退出

The partition table has been altered!

 

Calling ioctl() to re-read partition table.

Syncing disks. 

 

[root@mail ~]# fdisk /dev/sdc  #對第三塊硬盤進行分區

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

Building a new DOS disklabel. Changes willremain in memory only,

until you decide to write them. After that,of course, the previous

content won't be recoverable. 

 

The number of cylinders for this disk isset to 248029.

There is nothing wrong with that, but thisis larger than 1024,

and could in certain setups cause problemswith:

1) software that runs at boot time (e.g.,old versions of LILO)

2) booting and partitioning software fromother OSs

  (e.g., DOS FDISK, OS/2 FDISK)

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

 

Command (m for help): m  #列出全部幫助信息    

Command action

  a   toggle a bootable flag

  b   edit bsd disklabel

  c   toggle the dos compatibilityflag

  d   delete a partition

  l   list known partition types

  m   print this menu

  n   add a new partition

  o   create a new empty DOSpartition table

  p   print the partition table

  q   quit without saving changes

  s   create a new empty Sundisklabel

  t   change a partition's system id

  u   change display/entry units

  v   verify the partition table

  w   write table to disk and exit

  x   extra functionality (expertsonly)

 

Command (m for help): n   #建立新分區

Command action

  e   extended

  p   primary partition (1-4)

p  #建立主分區

Partition number (1-4): 1  #建立第一塊主分區

First cylinder (1-248029, default 1):

Using default value 1

Last cylinder or +size or +sizeM or +sizeK(1-248029, default 248029):

Using default value 248029

 

Command (m for help): t #更改分區的系統ID

Selected partition 1  #選擇第一個分區

Hex code (type L to list codes): 8e  #默認是linux格式，更改成Linux LVM

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

 

Command (m for help): w  #把當前配置信息寫入硬盤並退出

The partition table has been altered!

 

Calling ioctl() to re-read partition table.

Syncing disks. 

 

[root@mail ~]# fdisk /dev/sdd #對第四塊硬盤進行分區

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

Building a new DOS disklabel. Changes willremain in memory only,

until you decide to write them. After that,of course, the previous

content won't be recoverable.

 

 

The number of cylinders for this disk isset to 191145.

There is nothing wrong with that, but thisis larger than 1024,

and could in certain setups cause problemswith:

1) software that runs at boot time (e.g.,old versions of LILO)

2) booting and partitioning software fromother OSs

  (e.g., DOS FDISK, OS/2 FDISK)

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

 

Command (m for help): n #建立分區

Command action

  e   extended

  p   primary partition (1-4)

p  #建立主分區

Partition number (1-4): 1  #建立第一塊主分區

First cylinder (1-191145, default 1):

Using default value 1

Last cylinder or +size or +sizeM or +sizeK(1-191145, default 191145):

Using default value 191145

 

Command (m for help): t #更改分區的系統ID

Selected partition 1  #選擇第一個分區

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

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

 

Command (m for help): w  #把當前配置信息寫入硬盤並退出

The partition table has been altered!

 

Calling ioctl() to re-read partition table.

Syncing disks. 

 

 --------------------------------------------   如下是建立LV部分  -------------------------------------------------

 

[root@mail ~]# ls /dev/sd*  #查看當前系統有多少分區，能夠看到sdb，sdc，sdd這三塊硬盤都是分紅一個分區

/dev/sda /dev/sda1  /dev/sda2  /dev/sda3 /dev/sdb  /dev/sdb1  /dev/sdc /dev/sdc1  /dev/sdd  /dev/sdd1 

 

[root@mail ~]# pvcreate  /dev/sdb1    #sdb1轉換成physical volume【pv就是物理卷的意思】

 Physical volume "/dev/sdb1" successfully created

[root@mail ~]# pvcreate  /dev/sdc1   #sdc1轉換成physical volume

 Physical volume "/dev/sdc1" successfully created

[root@mail ~]# pvcreate  /dev/sdd1 #sdd1轉換成physical volume

 Physical volume "/dev/sdd1" successfully created

[root@mail ~]# pvs  #顯示當前系統全部的物理卷physical volume

 PV         VG                Fmt  Attr PSize  PFree

 /dev/sda1  VolGroup_ID_20054 lvm2a-     9.53G  9.53G

 /dev/sda3  VolGroup_ID_20054 lvm2a-   590.25G 54.50G

 /dev/sdb1                     lvm2 --     1.86T 1.86T

 /dev/sdc1                     lvm2--     1.86T  1.86T

 /dev/sdd1                     lvm2--     1.43T  1.43T

 [root@mail~]# vgcreate vg_de /dev/  sdb1 #建立卷組vg_de，並把sdb1加進來

  Nophysical volume label read from /dev/sdb1

 Physical volume "/dev/sdb1" successfully created

 Volume group "vg_de" successfully created

[root@mail ~]# vgextend  vg_de /dev/sdc1  #擴展卷組，把sdc1加進來

  Nophysical volume label read from /dev/sdc1

 Physical volume "/dev/sdc1" successfully created

 Volume group "vg_de" successfully extended

[root@mail ~]# vgextend  vg_de /dev/sdd1 #擴展卷組，把sdd1加進來

  Nophysical volume label read from /dev/sdd1

 Physical volume "/dev/sdd1" successfully created

 Volume group "vg_de" successfully extended

[root@mail ~]# vgs   #顯示系統全部卷組

 VG                #PV #LV #SNAttr   VSize   VFree

 VolGroup_ID_20054   2   6   0wz--n- 599.78G 64.03G

  vg_de              3   0   0wz--n-   5.14T  5.14T

 

[root@mail ~]# lvcreate -L 5.14T -n  lv_devg_de  #建立邏輯卷lv_de，並把卷組vg _de的空間資源所有分給其使用

 Rounding up size to full physical extent 5.14 TB

 Logical volume "lv_de" created

[root@mail ~]# lvs  #顯示系統全部邏輯卷

 LV         VG                Attr   LSize  Origin Snap%  Move Log Copy%  Convert

 LogVol0    VolGroup_ID_20054-wi-ao   4.00G                                     

 LogVol1    VolGroup_ID_20054-wi-ao  55.94G                                     

 LogVol2    VolGroup_ID_20054-wi-ao   9.88G                                      

 LogVol4    VolGroup_ID_20054-wi-ao  74.38G                                     

 LogVol5    VolGroup_ID_20054-wi-ao 268.00G                                     

 LogVolHome VolGroup_ID_20054 -wi-ao 123.56G                                      

  lv_de     vg_de            -wi-a-   5.14T  

                                  

[root@mail ~]# mkfs -t ext3 /dev/vg_de/lv_de #把lv_de格式化爲ext3格式

mke2fs 1.39 (29-May-2006)

Filesystem label=

OS type: Linux

Block size=4096 (log=2)

Fragment size=4096 (log=2)

689881088 inodes, 1379759104 blocks

68987955 blocks (5.00%) reserved for thesuper user

First data block=0

Maximum filesystem blocks=4294967296

42107 block groups

32768 blocks per group, 32768 fragments pergroup

16384 inodes per group

Superblock backups stored on blocks:

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

         4096000,7962624, 11239424, 20480000, 23887872, 71663616, 78675968,

         102400000,214990848, 512000000, 550731776, 644972544

 

Writing inode tables: done                           

Creating journal (32768 blocks): done

Writing superblocks and filesystemaccounting information: done

 

This filesystem will be automaticallychecked every 25 mounts or

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

 

[root@mail ~]# mount /dev/vg_de/lv_de  /local/  #把lv_de邏輯卷掛載到 /local/ 使用

 

[root@mail ~]# df –h #以易看懂的方式顯示當前全部掛載點空餘空間，df是disk  free的簡稱

文件系統              容量  已用 可用 已用% 掛載點

/dev/mapper/VolGroup_ID_20054-LogVol1

                       55G 465M   51G   1% /

/dev/mapper/VolGroup_ID_20054-LogVol2

                      9.6G  151M 9.0G   2% /tmp

/dev/mapper/VolGroup_ID_20054-LogVol4

                       73G  243M  69G   1% /var

/dev/mapper/VolGroup_ID_20054-LogVol5

                      260G 2.1G  245G   1% /usr

/dev/sda2             190M   16M 165M   9% /boot

tmpfs                 7.9G     0 7.9G   0% /dev/shm

/dev/mapper/VolGroup_ID_20054-LogVolHome

                      122G  219M 116G   1% /home

/dev/mapper/vg_de-lv_de

                      5.1T  188M 4.9T   1% /local

 

[root@mail ~]# vi /etc/fstab  #編輯磁盤開機掛載文件，使lv_de邏輯卷掛載到 /local/ 這個效果永久生效。對於Linux而言，一切沒有寫入文件的操做，關機重啓則無效

/dev/VolGroup_ID_20054/LogVol1     /          ext3    defaults          1  1

/dev/VolGroup_ID_20054/LogVol2    /tmp        ext3    defaults          1  2

/dev/VolGroup_ID_20054/LogVol4    /var        ext3     defaults         1  2

/dev/VolGroup_ID_20054/LogVol5    /usr         ext3     defaults         1  2

LABEL=/boot                      /boot       ext3     defaults          1  2

tmpfs                            /dev/shm    tmpfs    defaults         0  0

devpts                            /dev/pts    devpts   gid=5,mode=620  0  0

sysfs                              /sys       sysfs    defaults          0  0

proc                              /proc      proc      defaults         0  0

/dev/VolGroup_ID_20054/LogVol0     swap       swap    defaults           0  0

/dev/VolGroup_ID_20054/LogVolHome /home      ext3    defaults          1  2

/dev/vg_de/lv_de                   /local      ext3     defaults           0  2 

[root@mail ~]# reboot

-----------

題外話：做者本人當時編輯fstab文件的時候，加載LV磁盤的有些地方沒注意寫錯了，致使系統一重啓就找不到LV磁盤，進入到了單用戶維護模式，而此時 / 是隻讀的，根本沒辦法把有錯的地方改過來。後來發現能夠用 mount -n -o remount,rw / 的命令來從新掛載 / ，而後就能夠修改文件啦，這個命令頗有用，不管你是由於什麼緣由進到這樣的一個維護模式，均可以用這樣的命令，而後獲取對磁盤的寫入權限。