LVM快速入門

LVM筆記

[toc]

環境準備

• 準備磁盤分區：

  [root@centos6-node3 ~]# fdisk /dev/sdg
  Command (m for help): n
  Command action
  e   extended
  p   primary partition (1-4)
  p
  Partition number (1-4): 1
  First cylinder (131-261, default 131): 
  Using default value 1
  Last cylinder, +cylinders or +size{K,M,G} (131-261, default 261): +500M
  Command (m for help): t
  Partition number (1-4): 1
  Hex code (type L to list codes): 8e
  Changed system type of partition 3 to 8e (Linux LVM)
  Command (m for help): w
  The partition table has been altered!
  Calling ioctl() to re-read partition table.
  Syncing disks.

  按照上述的操作方法創建3個500M的分區，然後如下檢查

  [root@centos6-node3 ~]# fdisk -l
  Device Boot      Start         End      Blocks   Id  System
  /dev/sdg1               1          65      522081   8e  Linux LVM
  /dev/sdg2              66         130      522112+  8e  Linux LVM
  /dev/sdg3             131         195      522112+  8e  Linux LVM

  第一階段：準備PV（物理卷）

• 先創建和檢查pv

  [root@centos6-node3 ~]# pvcreate /dev/sdg1
  [root@centos6-node3 ~]# pvcreate /dev/sdg2
  [root@centos6-node3 ~]# pvcreate /dev/sdg3
  [root@centos6-node3 ~]# pvdisplay /dev/sdg1    #檢查pv情況
  --- NEW Physical volume ---
  PV Name               /dev/sdg1
  VG Name               
  PV Size               509.84 MiB
  Allocatable           NO
  PE Size               0   
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               tmkRdY-h9LX-V0h0-sTXI-lFZW-Cref-LcoCXE
  [root@centos6-node3 ~]# pvremove /dev/sdg3      #移除pv

準備卷組（VG）

• 創建VG

  [root@centos6-node3 ~]# vgcreate volume-group1 /dev/sdg1 /dev/sdg2
  [root@centos6-node3 ~]# vgdisplay      #查看VG信息
  --- Volume group ---
  VG Name               volume-group1
  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 LV               0
  Max PV                0
  Cur PV                2
  Act PV                2
  VG Size               1016.00 MiB
  PE Size               4.00 MiB
  Total PE              254
  Alloc PE / Size       0 / 0   
  Free  PE / Size       254 / 1016.00 MiB
  VG UUID               NZfaUa-lchX-qQLk-WdtO-clN8-msE2-b3q6YP

• 刪除VG

  [root@centos6-node3 ~]# vgremove volume-group1

  準備邏輯卷（LV）

• 創建LV

  root@centos6-node3 ~]# lvcreate -L 100M -n lv1 volume-group1    #從VG畫出100M的空間作爲lv1
  [root@centos6-node3 ~]# lvdisplay    #查看lv
  /dev/md126: read failed after 0 of 4096 at 0: Input/output error
  --- Logical volume ---
  LV Path                /dev/volume-group1/lv1
  LV Name                lv1
  VG Name                volume-group1
  LV UUID                Aq4zSR-Rc3A-l4lv-7aoS-qADe-4Q1I-vhGUe1
  LV Write Access        read/write
  LV Creation host, time centos6-node3, 2017-12-12 23:08:44 +0800
  LV Status              available
  # open                 0
  LV Size                100.00 MiB
  Current LE             25
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:2

  最後一步，將LV格式化並掛載

• 格式化&初始化：

  [root@centos6-node3 ~]# mkfs.ext4 /dev/volume-group1/lv1  #格式化
  [root@centos6-node3 ~]# mkdir /mnt/lvm-mount
  [root@centos6-node3 ~]# mount /dev/volume-group1/lv1 /mnt/lvm-mount   #掛載
  [root@centos6-node3 ~]# dd if=/dev/zero of=/mnt/lvm-mount/test1 bs=1M count=89    #數據寫入

• 刪除LV

  [root@centos6-node3 ~]# umount /mnt/lvm-mount/    #要先卸載
  [root@centos6-node3 lvm-mount]# lvremove /dev/volume-group1/lv1      #刪除LV（高危操作）

• 拓展LVM卷

  [root@centos6-node3 lvm-mount]# umount /mnt/lvm-mount/   #擴容之前一定要卸載
  [root@centos6-node3 lvm-mount]# lvresize -L 200M /dev/volume-group1/lv1     #擴容200M
  [root@centos6-node3 lvm-mount]# e2fsck -f /dev/volume-group1/lv1      #檢查磁盤錯誤
  [root@centos6-node3 ~]# resize2fs /dev/volume-group1/lv1    #更新lv
  [root@centos6-node3 ~]# lvdisplay     #檢查lv1
  /dev/md126: read failed after 0 of 4096 at 0: Input/output error
  --- Logical volume ---
  LV Path                /dev/volume-group1/lv1
  LV Name                lv1
  VG Name                volume-group1
  LV UUID                emCezv-2nBN-0vgu-y54a-R93P-KCBG-SSF7ZI
  LV Write Access        read/write
  LV Creation host, time centos6-node3, 2017-12-12 23:21:15 +0800
  LV Status              available
  # open                 0
  LV Size                200.00 MiB
  Current LE             50
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:2
  [root@centos6-node3 ~]# mount /dev/volume-group1/lv1 /mnt/lvm-mount/   #掛盤即可

• LVM縮容
• 卸載卷

  [root@centos6-node3 ~]# df    #回家目錄卸載，不然會報錯
  Filesystem           1K-blocks    Used Available Use% Mounted on
  /dev/mapper/vg_centos6node3-lv_root
                    38645208 1022088  35653356   3% /
  tmpfs                   502056       0    502056   0% /dev/shm
  /dev/sda1               487652   52916    409136  12% /boot
  /dev/mapper/volume--group1-lv1
                      194466   92687     91539  51% /mnt/lvm-mount
  [root@centos6-node3 ~]# umount /dev/mapper/volume--group1-lv1
  [root@centos6-node3 ~]# e2fsck -f /dev/volume-group1/lv1    #檢查磁盤錯誤

• 縮容

  [root@centos6-node3 ~]# resize2fs /dev/volume-group1/lv1 100M  #縮小文件系統
  [root@centos6-node3 ~]# lvresize -L 100M /dev/volume-group1/lv1   #減小邏輯卷的大小
  [root@centos6-node3 ~]# lvdisplay     #檢查是否縮小了100M
  /dev/md126: read failed after 0 of 4096 at 0: Input/output error
  --- Logical volume ---
  LV Path                /dev/volume-group1/lv1
  LV Name                lv1
  VG Name                volume-group1
  LV UUID                emCezv-2nBN-0vgu-y54a-R93P-KCBG-SSF7ZI
  LV Write Access        read/write
  LV Creation host, time centos6-node3, 2017-12-12 23:21:15 +0800
  LV Status              available
  # open                 0
  LV Size                100.00 MiB
  Current LE             25
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:2

  其他問題

  拓展卷組

  讓我們假設我們的卷組'volume-group1'已經滿了，需要擴大。手上的硬盤（sdg）已經沒有其他空閒分區，我們添加了另外一個硬盤（sdc）。我們將看到如何把sdc的分區添加到卷組以擴展。

• 檢查卷組狀態：

  [root@centos6-node3 ~]# vgdisplay volume-group1 
  /dev/md126: read failed after 0 of 4096 at 0: Input/output error
  --- Volume group ---
  VG Name               volume-group1
  System ID             
  Format                lvm2
  Metadata Areas        2
  Metadata Sequence No  6
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                1
  Open LV               0
  Max PV                0
  Cur PV                2
  Act PV                2
  VG Size               1016.00 MiB
  PE Size               4.00 MiB
  Total PE              254
  Alloc PE / Size       25 / 100.00 MiB
  Free  PE / Size       229 / 916.00 MiB
  VG UUID               QgBiHO-391u-jrra-QfiG-BKhF-GCBR-EuhEY0

• 初始化一個分區

  [root@centos6-node3 ~]# fdisk /dev/sdf
  Command (m for help): n
  Command action
  e   extended
  p   primary partition (1-4)
  p
  Partition number (1-4): 1
  First cylinder (1-261, default 1): 
  Using default value 1
  Last cylinder, +cylinders or +size{K,M,G} (1-261, default 261): 
  Using default value 261
  Command (m for help): t
  Selected partition 1
  Hex code (type L to list codes): 8e
  Changed system type of partition 1 to 8e (Linux LVM)
  Command (m for help): p
  Disk /dev/sdf: 2147 MB, 2147483648 bytes
  255 heads, 63 sectors/track, 261 cylinders
  Units = cylinders of 16065 * 512 = 8225280 bytes
  Sector size (logical/physical): 512 bytes / 512 bytes
  I/O size (minimum/optimal): 512 bytes / 512 bytes
  Disk identifier: 0x27eee55a
  Device Boot      Start         End      Blocks   Id  System
  /dev/sdf1               1         261     2096451   8e  Linux LVM
  Command (m for help): w
  The partition table has been altered!
  Calling ioctl() to re-read partition table.
  WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
  The kernel still uses the old table. The new table will be used at
  the next reboot or after you run partprobe(8) or kpartx(8)
  Syncing disks.

• 創建pv

  [root@centos6-node3 ~]# pvcreate /dev/sdf1

• 拓展vg

  [root@centos6-node3 ~]# vgextend volume-group1 /dev/sdg3
  [root@centos6-node3 ~]# vgdisplay volume-group1   #檢查是否擴容