linux lvm管理

LVM
一、lvm相关概念
   pv   ##物理卷    pe   ##物理扩展
   vg   ##卷组     lvm   ##逻辑卷

二、设置lvm分区挂载
  1.建立分区，设置lvm类型
  Command (m for help): t
   Partition number (1,2, default 2): 1
   Hex code (type L to list all codes): 8e
   Changed type of partition 'Linux' to 'Linux LVM'
  2.同步分区表  partprobe
  3.将物理分区变为物理卷  pvcreate /dev/vdb1

  [[email protected] ~]# pvcreate /dev/vdb1

   WARNING: xfs signature detected on /dev/vdb1 at offset 0. Wipe it? [y/n] y
  Wiping xfs signature on /dev/vdb1.
  Physical volume "/dev/vdb1" successfully created
  4.将物理卷变为卷组  vgcreate vg0 /dev/vdb1
  [[email protected] ~]# vgcreate vg0 /dev/vdb1

   Volume group "vg0" successfully created

  5.建立逻辑卷 lvcreate -L 100M -n lv0 vg0
    -L   ##指定逻辑卷大小     -n   ##指定逻辑卷名字
  [[email protected] ~]# lvcreate -L 100M -n lv0 vg0
  WARNING: linux_raid_member signature detected on /dev/vg0/lv0 at offset 4096. Wipe it? [y/n] y
  Wiping linux_raid_member signature on /dev/vg0/lv0.

  Logical volume "lv0" created

  6.格式化  mkfs.xfs /dev/vg0/lv0

  7.挂载  mount /dev/vg0/lv0 /data

 
三、逻辑卷/卷组管理
  1.扩展逻辑卷/卷组
    扩展逻辑卷  lvextend -L 200M /dev/vg0/lv0
    [[email protected] ~]# lvextend -L 200M /dev/vg0/lv0
     Extending logical volume lv0 to 200.00 MiB

     Logical volume lv0 successfully resized

    扩展挂载的文件系统  xfs_growfs /dev/vg0/lv0

    扩展卷组：当卷组内存用完时

    建立新的物理卷  pvcreate /dev/vdb2

    扩展卷组  vgextend vg0 /dev/vdb2

    然后可以正常扩展逻辑卷
  2.缩减逻辑卷/卷组
    注意：xfs文件系统不能缩减，需要ext4文件系统
    卸载  umount /data

    将文件系统格式化为ext4   mkfs.ext4 /dev/vg0/lv0

    扫描文件（为了缩减时保留足够的内存）

    [[email protected] ~]# e2fsck -f /dev/vg0/lv0

     e2fsck 1.42.9 (28-Dec-2013)
     Pass 1: Checking inodes, blocks, and sizes
     Pass 2: Checking directory structure
     Pass 3: Checking directory connectivity
     Pass 4: Checking reference counts
     Pass 5: Checking group summary information
    /dev/vg0/lv0: 11/44832 files (0.0% non-contiguous), 7272/179200 blocks

     缩减文件系统  resize2fs /dev/vg0/lv0 100M

     挂载  mount /dev/vg0/lv0 /data

     缩减逻辑卷   lvreduce -L 200M /dev/vg0/lv0

   [[email protected] ~]# lvreduce -L 200M /dev/vg0/lv0
    WARNING: Reducing active and open logical volume to 200.00 MiB
    THIS MAY DESTROY YOUR DATA (filesystem etc.)
    Do you really want to reduce lv0? [y/n]: y
    Reducing logical volume lv0 to 200.00 MiB
    Logical volume lv0 successfully resized
     若要移出物理卷1，但物理卷1被占用
     则：将物理卷1数据转移至物理卷2

    [[email protected] ~]# pvmove /dev/vdb1 /dev/vdb2

     /dev/vdb1: Moved: 2.0%
     /dev/vdb1: Moved: 100.0%
     然后正常移出物理卷1

    [[email protected] ~]# vgreduce vg0 /dev/vdb1

     Removed "/dev/vdb1" from volume group "vg0"

四、逻辑卷lvm快照
     在/data下建立文件（即数据存储）

     建立快照   lvcreate -L 20M -n lv0-backup -s /dev/vg0/lv0

       

     挂载  mount /dev/vg0/lv0-backup /mnt

         

     编辑快照，若毁坏，则：

      卸载    umount /mnt

      移除    lvremove /dev/vg0/lv0-backup

      快照    lvcreate -L 20M -n lv0-backup -s /dev/vg0/lv0

      挂载    mount /dev/vg0/lv0-backup /mnt

五、删除lvm
   1.卸载所有的挂载点

    [[email protected] ~]# umount /mnt

    [[email protected] ~]# umount /data

   2.移除逻辑卷（源文件和快照）

    [[email protected] ~]# lvremove /dev/vg0/lv0-backup

     Do you really want to remove active logical volume lv0-backup? [y/n]: y
    Logical volume "lv0-backup" successfully removed

    [[email protected] ~]# lvremove /dev/vg0/lv0

     Do you really want to remove active logical volume lv0? [y/n]: y
    Logical volume "lv0" successfully removed
   3.移除卷组

    [[email protected] ~]# vgremove vg0

   4.移除所有的物理卷

    [[email protected] ~]# pvremove /dev/vdb1

     Labels on physical volume "/dev/vdb1" successfully wiped

    [[email protected] ~]# pvremove /dev/vdb2

     Labels on physical volume "/dev/vdb2" successfully wiped
   5.查看移除结果（ok）
     [[email protected] ~]# pvs