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 cylindersUnits = 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 cylindersUnits = 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 cylindersUnits = 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/hdb2mke2fs 1.39 (29-May-2006)Filesystem label=OS type: LinuxBlock size=4096 (log=2)Fragment size=4096 (log=2)137088 inodes, 274176 blocks13708 blocks (5.00%) reserved for the super userFirst data block=0Maximum filesystem blocks=2810183689 block groups32768 blocks per group, 32768 fragments per group15232 inodes per groupSuperblock backups stored on blocks: 32768, 98304, 163840, 229376

Checking for bad blocks (read-only test): done

Writing inode tables: done Creating journal (8192 blocks): doneWriting 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 -hvFilesystem Size Used Avail Use% Mounted on/dev/hda3 17G 9.8G 5.8G 64% //dev/hda1 99M 18M 76M 20% /boottmpfs 217M 0 217M 0% /dev/shmnone 217M 104K 217M 1% /var/lib/xenstored/dev/mapper/vg01_pgdata-lv_pgdata11008M 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% /boottmpfs 217M 0 217M 0% /dev/shmnone 217M 104K 217M 1% /var/lib/xenstored/dev/mapper/vg01_pgdata-lv_pgdata11008M 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_pgdata1resize2fs 1.39 (29-May-2006)Filesystem at /dev/mapper/vg01_pgdata-lv_pgdata1 is mounted on /database/pgdata1; on-line resizing requiredPerforming 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 -hvFilesystem Size Used Avail Use% Mounted on/dev/hda3 17G 9.8G 5.8G 64% //dev/hda1 99M 18M 76M 20% /boottmpfs 217M 0 217M 0% /dev/shmnone 217M 104K 217M 1% /var/lib/xenstored/dev/mapper/vg01_pgdata-lv_pgdata11.5G 34M 1.4G 3% /database/pgdata1 备注：目录 /database/pgdata1 空间果然变大了。