linux調整lvm分區大小

    最近開始搗鼓linux，把開發環境轉到linux上。。。因爲本人有怪癖。。不喜歡集成包。。因此apache+php+mysql相關的開發環境都是手動編譯的。。

    在安裝centos的時候因爲對分區不熟悉，選擇了默認分區，致使在安裝mysql的時候，沒有一個單獨的分區來存放data。只能研究下如何調整lvm卷的大小了。。

    用vgdisplay指令查看vg卷的大小

[root@localhost caoyong]# vgdisplay
  --- Volume group ---
  VG Name               vg_centoscy
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  8
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                4
  Open LV               4
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               465.27 GiB
  PE Size               4.00 MiB
  Total PE              119109
  Alloc PE / Size       119109 / 465.27 GiB
  Free  PE / Size       0 / 0   
  VG UUID               LKnVzD-DeMj-Fonv-zR9Z-vCHs-1TMl-2ELian

VG Name           卷組名稱
Alloc PE / Size   卷組總空間

Free PE / Size   卷組剩餘空間

vg_centoscy卷組中已經沒有剩餘空間讓我分割給其餘lvm，所以咱們要從其餘lvm中分割一部分空間出來

使用lvdisplay指令查看vg_centoscy到lvm分配狀況

[root@localhost caoyong]# lvdisplay vg_centoscy
  --- Logical volume ---
  LV Path                /dev/vg_centoscy/lv_root
  LV Name                lv_root
  VG Name                vg_centoscy
  LV UUID                4rlwmS-6ZZT-nGFE-aKgl-KZaW-FlUn-fMA9of
  LV Write Access        read/write
  LV Creation host, time centos-cy, 2010-01-04 10:42:37 +0800
  LV Status              available
  # open                 1
  LV Size                50.00 GiB
  Current LE             12800
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0
   
  --- Logical volume ---
  LV Path                /dev/vg_centoscy/lv_home
  LV Name                lv_home
  VG Name                vg_centoscy
  LV UUID                IknYf3-lhXg-3qAU-kEum-Nhyj-2kiZ-SBdmHg
  LV Write Access        read/write
  LV Creation host, time centos-cy, 2010-01-04 10:42:47 +0800
  LV Status              available
  # open                 1
  LV Size                400.00 GiB
  Current LE             102400
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:2
   
  --- Logical volume ---
  LV Path                /dev/vg_centoscy/lv_swap
  LV Name                lv_swap
  VG Name                vg_centoscy
  LV UUID                8pOAL1-o0kr-0glK-jJve-G6Oo-8mZM-DHxgPE
  LV Write Access        read/write
  LV Creation host, time centos-cy, 2010-01-04 10:44:04 +0800
  LV Status              available
  # open                 1
  LV Size                3.72 GiB
  Current LE             952
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:1
   
  --- Logical volume ---
  LV Path                /dev/vg_centoscy/data
  LV Name                data
  VG Name                vg_centoscy
  LV UUID                p0X3ih-jDiQ-GN3B-R9Zd-U8qI-loSF-Sql6sc
  LV Write Access        read/write
  LV Creation host, time localhost.localdomain, 2012-12-28 13:07:42 +0800
  LV Status              available
  # open                 1
  LV Size                11.55 GiB
  Current LE             2957
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:3

能夠看到，lv_home的空間所最多的，路徑爲/dev/vg_centoscy/lv_home，在安裝系統的時候，lv_home卷是掛載到/home的，因而決定從這個最大到lvm中分割一部分空間出來

lvm的空間調整指令是

lvextend 增長lvm空間

lvreduce 減小lvm空間

這裏使用-L 參數指定須要調整到大小

例如lvextend -L 450G /dev/vg_centoscy/lv_home 表示將lv_home卷的大小調整到450G，前提是vg中有足夠的空間。注意，lvextend指令所指定到大小必須大於須要調整到lvm的大小

-L指令也能夠用 + 來調整大小 表示當前空間須要增長到大小 好比 -L +50G 表示lv_home卷的空間調整爲400G+50G

lvreduce指令跟lvextend指令徹底相反，這裏就不仔細說明了

[root@localhost caoyong]# lvreduce -L -10G -f /dev/vg_centoscy/lv_home
  WARNING: Reducing active and open logical volume to 390.00 GiB
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
  Reducing logical volume lv_home to 390.00 GiB
  Logical volume lv_home successfully resized

執行指令以後，lv_home的空間已經降低到390G，咱們能夠用lvdisplay來查看

接下來建立新的lvm

lvmcreate -L 10G -n mylvm /dev/vg_centoscy

[root@localhost caoyong]# lvcreate -L 10G -n mylvm /dev/vg_centoscy
  Logical volume "mylvm" created

在vg_centoscy卷組中建立mylvm卷，咱們使用lvdisplay指令查看，mylvm卷已經建立完成，接下來要將lvm掛載到linux的 / 中

建立/mylvm 分區

[root@localhost caoyong]# mkdir /mylvm

格式化mylvm卷

[root@localhost caoyong]# mke2fs -j -t ext4 /dev/vg_centoscy/mylvm
mke2fs 1.41.12 (17-May-2010)
文件系統標籤=
操做系統:Linux
塊大小=4096 (log=2)
分塊大小=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
655360 inodes, 2621440 blocks
131072 blocks (5.00%) reserved for the super user
第一個數據塊=0
Maximum filesystem blocks=2684354560
80 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks: 
	32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632

正在寫入inode表: 完成                            
Creating journal (32768 blocks): 完成
Writing superblocks and filesystem accounting information: 完成

This filesystem will be automatically checked every 35 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.

掛載mylvm捲到/mylvm分區

[root@localhost caoyong]# mount -t ext4 /dev/vg_centoscy/mylvm /mylvm

到這裏，lvm卷的分割，建立和掛載完成。

上述mylvm卷是在寫博文時查看指令和運行結果所臨時分割的空間，data卷是以前操做中分割給mysql做爲數據儲存用的空間。本人初學linux，有什麼遺漏到地方但願有人指正