这节主要演练在线扩容 VG 和 LV 。
一 动态扩容 VG
--1.1 查看硬盘信息
[root@pgb lvm]# fdisk -l
Disk /dev/hda: 19.3 GB, 19327352832 bytes
255 heads, 63 sectors/track, 2349 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/hda1 * 1 13 104391 83 Linux
/dev/hda2 14 144 1052257+ 82 Linux swap / Solaris
/dev/hda3 145 2349 17711662+ 83 Linux
Disk /dev/hdb: 2147 MB, 2147483648 bytes
16 heads, 63 sectors/track, 4161 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Device Boot Start End Blocks Id System
/dev/hdb1 1 1985 1000408+ 83 Linux
/dev/hdb2 1986 4161 1096704 83 Linux
Disk /dev/hdd: 1073 MB, 1073741824 bytes
16 heads, 63 sectors/track, 2080 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Device Boot Start End Blocks Id System
/dev/hdd1 1 2080 1048288+ 83 Linux
[root@pgb lvm]# pvscan
PV /dev/hdb1 VG vg01_pgdata lvm2 [976.00 MB / 972.00 MB free]
PV /dev/hdd1 VG vg01_pgdata lvm2 [1020.00 MB / 0 free]
Total: 2 [1.95 GB] / in use: 2 [1.95 GB] / in no VG: 0 [0 ]
备注：根据 fdisk 和 pvscan 命令输出，知道 /dev/hdb2 还没有加入 VG， 可以使用，
接下来将 /dev/hdb2 加入 VG vg01_pgdata。
--1.2 查看 VG 信息
[root@pgb lvm]# vgdisplay
--- Volume group ---
VG Name vg01_pgdata
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 2
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 2
Act PV 2
VG Size 1.95 GB
PE Size 4.00 MB
Total PE 499
Alloc PE / Size 256 / 1.00 GB
Free PE / Size 243 / 972.00 MB
VG UUID B5pg8R-2AGm-6DEp-K7HK-TI1I-HC3h-gWx32m
--1.3 格式化文件系统
[root@pgb lvm]# mkfs -t ext3 -c /dev/hdb2
mke2fs 1.39 (29-May-2006)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
137088 inodes, 274176 blocks
13708 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=281018368
9 block groups
32768 blocks per group, 32768 fragments per group
15232 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376
Checking for bad blocks (read-only test): done
Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 28 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
--1.4 创建PV
[root@pgb lvm]# pvcreate /dev/hdb2
Physical volume "/dev/hdb2" successfully created
--1.5 在线扩容 VG
[root@pgb lvm]# vgs
VG #PV #LV #SN Attr VSize VFree
vg01_pgdata 2 1 0 wz--n- 1.95G 972.00M
[root@pgb lvm]# vgextend vg01_pgdata /dev/hdb2
Volume group "vg01_pgdata" successfully extended
[root@pgb lvm]# vgs
VG #PV #LV #SN Attr VSize VFree
vg01_pgdata 3 1 0 wz--n- 2.99G 1.99G
--1.6 再次查看 VG，查看是否扩容
[root@pgb lvm]# vgdisplay
--- Volume group ---
VG Name vg01_pgdata
System ID
Format lvm2
Metadata Areas 3
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 3
Act PV 3
VG Size 2.99 GB
PE Size 4.00 MB
Total PE 766
Alloc PE / Size 256 / 1.00 GB
Free PE / Size 510 / 1.99 GB
VG UUID B5pg8R-2AGm-6DEp-K7HK-TI1I-HC3h-gWx32m
备注：现在 vg01_pgdata 大小为 3 GB 左右，已成功扩容 1 GB。
二 动态扩容 LV
目标给已在线上使用的LV 扩容，在以下例子中，给目录 /database/pgdata1 扩容 512 M。
--2.1 查看目录使用情况
[root@pgb lvm]# df -hv
Filesystem Size Used Avail Use% Mounted on
/dev/hda3 17G 9.8G 5.8G 64% /
/dev/hda1 99M 18M 76M 20% /boot
tmpfs 217M 0 217M 0% /dev/shm
none 217M 104K 217M 1% /var/lib/xenstored
/dev/mapper/vg01_pgdata-lv_pgdata1
1008M 34M 924M 4% /database/pgdata1
--2.2 查看所属 VG 信息
[root@pgb lvm]# vgdisplay
--- Volume group ---
VG Name vg01_pgdata
System ID
Format lvm2
Metadata Areas 3
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 3
Act PV 3
VG Size 2.99 GB
PE Size 4.00 MB
Total PE 766
Alloc PE / Size 256 / 1.00 GB
Free PE / Size 510 / 1.99 GB
VG UUID B5pg8R-2AGm-6DEp-K7HK-TI1I-HC3h-gWx32m
备注：从上面看出，VG vg01_pgdata 最大可用空间为 2.99 GB, 目前已分配 1 GB，还剩余 1.99 GB 可以分配。
--2.3 增加 LV 大小
[root@pgb lvm]# lvextend -L +512M /dev/mapper/vg01_pgdata-lv_pgdata1
Extending logical volume lv_pgdata1 to 1.50 GB
Logical volume lv_pgdata1 successfully resized
[root@pgb lvm]# df -hv
Filesystem Size Used Avail Use% Mounted on
/dev/hda3 17G 9.9G 5.8G 64% /
/dev/hda1 99M 18M 76M 20% /boot
tmpfs 217M 0 217M 0% /dev/shm
none 217M 104K 217M 1% /var/lib/xenstored
/dev/mapper/vg01_pgdata-lv_pgdata1
1008M 34M 924M 4% /database/pgdata1
备注： LV 扩容成功，但目录 /database/pgdata1 大小仍然为 1G，没有变化。
还需要 resize2fs 命令处理下。
--2.4 resize2fs
[root@pgb lvm]# resize2fs -f /dev/mapper/vg01_pgdata-lv_pgdata1
resize2fs 1.39 (29-May-2006)
Filesystem at /dev/mapper/vg01_pgdata-lv_pgdata1 is mounted on /database/pgdata1; on-line resizing required
Performing an on-line resize of /dev/mapper/vg01_pgdata-lv_pgdata1 to 524288 (4k) blocks.
The filesystem on /dev/mapper/vg01_pgdata-lv_pgdata1 is now 524288 blocks long.
--2.5 再次查看
[root@pgb lvm]# df -hv
Filesystem Size Used Avail Use% Mounted on
/dev/hda3 17G 9.8G 5.8G 64% /
/dev/hda1 99M 18M 76M 20% /boot
tmpfs 217M 0 217M 0% /dev/shm
none 217M 104K 217M 1% /var/lib/xenstored
/dev/mapper/vg01_pgdata-lv_pgdata1
1.5G 34M 1.4G 3% /database/pgdata1
备注：目录 /database/pgdata1 空间果然变大了。
转载http://francs3.blog.163.com/blog/static/405767272012122444797/