Linux下使用LVM动态扩展磁盘空间

1、1.查看磁盘信息： rootlg-centos # df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg_lgcentos-lv_root 16G 9.8G 5.4G 65% / tmpfs 948M 72K 948M 1% /dev/shm /dev/sda1 485M 61M 399M 14% /boot rootlg-centos # fdisk -l Disk /dev/sda: 21.5 GB, 21474836480 bytes 255 heads, 63 sectors/track, 2610 cylind

2、ers 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: 0x000402bd Device Boot Start End Blocks Id System /dev/sda1 * 1 64 512000 83 Linux Partition 1 does not end on cylinder boundary

3、. /dev/sda2 64 2611 20458496 8e Linux LVM Disk /dev/sdb: 32.2 GB, 32212254720 bytes 255 heads, 63 sectors/track, 3916 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: 0x00

4、000000 Disk /dev/mapper/vg_lgcentos-lv_root: 16.7 GB, 166* bytes 255 heads, 63 sectors/track, 2028 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: 0x00000000 Disk /dev/ma

5、pper/vg_lgcentos-lv_swap: 4261 MB, 4261412864 bytes 255 heads, 63 sectors/track, 518 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: 0x00000000 2.给/dev/sdb添加分区/dev/sdb1 2

6、.1 fdisk /dev/sdb m 查看帮助 n 添加新分区 t 修改分区类型为：8e=>Linux LVM p 查看分区 w 写入分区表并退出 q 不保存分区表并退出 3.扩展逻辑卷/dev/mapper/vg_lgcentos-lv_root的大小 3.1输入lvm，进入LVM管理器(此步骤可省略，直接进行下面的操作，效果完全一样 3.2将分区转换为物理卷，此步骤可省略:当将分区直接添加到卷组时，LVM会自动将分区转换为物理卷组。这里跳过这一步 lvm> pvcreate /dev/sdb1 Physical volume "/dev/sdb1" suc

7、cessfully created 相反过程：将物理卷还原为普通分区 lvm> pvremove /dev/sdb1 Labels on physical volume "/dev/sdb1" successfully wiped 3.3将物理卷添加到现有卷组 lvm> vgextend vg_lgcentos /dev/sdb1 No physical volume label read from /dev/sdb1 Physical volume "/dev/sdb1" successfully created Volume group

8、"vg_lgcentos" successfully extended 相反过程,将物理卷移除卷组 lvm> vgreduce vg_lgcentos /dev/sdb1 Removed "/dev/sdb1" from volume group "vg_lgcentos" 3.4使用pvscan命令查看所有物理卷及所属分组 lvm> pvscan PV /dev/sda2 VG vg_lgcentos lvm2 19.51 GiB / 0 free PV /dev/sdb1 VG vg_lgcentos lvm2 30.

9、00 GiB / 30.00 GiB free Total: 2 49.50 GiB / in use: 2 49.50 GiB / in no VG: 0 0 3.5查看所有逻辑卷 lvm> lvscan ACTIVE '/dev/vg_lgcentos/lv_root' 15.54 GiB inherit ACTIVE '/dev/vg_lgcentos/lv_swap' 3.97 GiB inherit 3.6扩展逻辑卷大小 lvm> lvextend -L +30G /dev/vg_lgcentos/lv_root Extending log

10、ical volume lv_root to 45.54 GiB Insufficient free space: 7680 extents needed, but only 7679 available 注意：上面虽然显示物理卷/dev/sdb1有30.00 GiB空闲，但是这里不能全部使用，29.99G是可以的. lvm> lvextend -L +29.99G /dev/vg_lgcentos/lv_root Rounding size to boundary between physical extents: 29.99 GiB Extending logical volume

11、lv_root to 45.54 GiB Logical volume lv_root successfully resized 相反过程：减小逻辑卷的大小 lvm> lvreduce -L -7697 /dev/vg_lgcentos/lv_root Rounding size to boundary between physical extents: 7.52 GiB WARNING: Reducing active and open logical volume to 15.54 GiB THIS MAY DESTROY YOUR DATA (filesystem etc. Do

12、you really want to reduce lv_root? y/n: y Reducing logical volume lv_root to 15.54 GiB Logical volume lv_root successfully resized 3.7查看物理卷和逻辑卷 lvm> lvscan ACTIVE '/dev/vg_lgcentos/lv_root' 45.54 GiB inherit ACTIVE '/dev/vg_lgcentos/lv_swap' 3.97 GiB inherit lvm> pvscan PV /dev

13、/sda2 VG vg_lgcentos lvm2 19.51 GiB / 0 free PV /dev/sdb1 VG vg_lgcentos lvm2 30.00 GiB / 0 free Total: 2 49.50 GiB / in use: 2 49.50 GiB / in no VG: 0 0 3.8虽然这里显示已经将物理卷的空间添加到了逻辑卷上，但是使用df -h命令查看逻辑卷还是没有变化，fdisk -l缺已经生效了，因为还差最后一步激活 rootlg-centos # df -h Filesystem Size Used Avail Use% Mounted on /dev/

14、mapper/vg_lgcentos-lv_root 16G 9.8G 5.4G 65% / tmpfs 948M 72K 948M 1% /dev/shm /dev/sda1 485M 61M 399M 14% /boot rootlg-centos # fdisk -l Disk /dev/sda: 21.5 GB, 21474836480 bytes 255 heads, 63 sectors/track, 2610 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physic

15、al: 512 bytes / 512 bytes I/O size (minimum/optimal: 512 bytes / 512 bytes Disk identifier: 0x000402bd Device Boot Start End Blocks Id System /dev/sda1 * 1 64 512000 83 Linux Partition 1 does not end on cylinder boundary. /dev/sda2 64 2611 20458496 8e Linux LVM Disk /dev/sdb: 32.2 GB, 32212254720 bytes 255 heads, 63 sectors/track, 3916 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physic