yum服务器lvm扩容，data目录是yum存放rpm包的目录，只有20G，需要添加磁盘扩容到80G
# df -lh
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_node5-root 20G 479M 18G 3% /
tmpfs 935M 0 935M 0% /dev/shm
/dev/sda1 485M 39M 421M 9% /boot
/dev/mapper/vg_node5-data 20G 172M 19G 1% /data
/dev/mapper/vg_node5-usr 9.7G 1.6G 7.6G 18% /usr
/dev/mapper/vg_node5-web 15G 165M 14G 2% /web
1.添加一块硬盘
2.对硬盘分区，并将格式调整为8e即linux lvm格式
#挂载系统分区
# kpartx -l /dev/sdb
# kpartx -af /dev/sdb
# partx -a /dev/sdb
3.创建物理卷
在将几块盘做LVM时，遇到一个之前都没遇到过的问题:
# pvcreate /dev/sdb5
Can't open /dev/sdb5 exclusively. Mounted filesystem?
首先第一反应就是查看这个分区是否已经在使用了，但是没有。
查看硬盘的一些信息:
# cat /proc/partitions
major minor #blocks name
8 0 83886080 sda
8 1 512000 sda1
8 2 83373056 sda2
8 16 125829120 sdb
8 17 1 sdb1
8 21 125796982 sdb5
253 0 20480000 dm-0
253 1 4096000 dm-1
253 2 15360000 dm-2
253 3 20480000 dm-3
253 4 10240000 dm-4
253 5 1 dm-5
253 6 125796982 dm-6
# fdisk /dev/sdb -l
Disk /dev/sdb: 128.8 GB, 128849018880 bytes
255 heads, 63 sectors/track, 15665 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: 0x44c662ff
Device Boot Start End Blocks Id System
/dev/sdb1 1 15665 125829081 5 Extended
/dev/sdb5 5 15665 125796982+ 8e Linux LVM
接着看一些底层的信息:
dmsetup 是一个底层的逻辑卷管理， dm 应该是 Device Mapper的简称。
[root@node5 /]# dmsetup status
sdb1: 0 2 linear
vg_node5-web: 0 30720000 linear
sdb5: 0 251593965 linear
vg_node5-usr: 0 20480000 linear
vg_node5-swap: 0 8192000 linear
vg_node5-root: 0 40960000 linear
vg_node5-data: 0 40960000 linear
[root@node5 /]# dmsetup ls
sdb1 (253:5)
vg_node5-web (253:2)
sdb5 (253:6)
vg_node5-usr (253:4)
vg_node5-swap (253:1)
vg_node5-root (253:0)
vg_node5-data (253:3)
例如：
root@ubuntu:~# dmsetup ls
35000c50026716847 (254, 2)
vg_data-lv_home (254, 0)
35000c5002670f03e (254, 3)
35000c5002670f03e-part1 (254, 5)
35000c50026716847-part1 (254, 4)
vg_data-lv_swap (254, 1)
可以看到 35000c5002670f03e 和 35000c50026716847 组成了multipath(多路径)
# ll /dev/mapper/
total 0
crw-rw---- 1 root root 10, 58 Jul 26 19:51 control
lrwxrwxrwx 1 root root 7 Jul 26 19:59 vg_node5-data -> ../dm-3
lrwxrwxrwx 1 root root 7 Jul 26 19:59 /dev/sdb1 -> ../dm-5
lrwxrwxrwx 1 root root 7 Jul 26 19:59 /dev/sdb5 -> ../dm-6
lrwxrwxrwx 1 root root 7 Jul 26 19:59 vg_node5-root -> ../dm-0
lrwxrwxrwx 1 root root 7 Jul 26 19:59 vg_node5-swap -> ../dm-1
lrwxrwxrwx 1 root root 7 Jul 26 19:59 vg_node5-usr -> ../dm-4
lrwxrwxrwx 1 root root 7 Jul 26 19:59 vg_node5-web -> ../dm-2
使用 dmsetup remove xxx 移除掉就可以创建PV了:
# dmsetup remove /dev/sdb1
# dmsetup remove /dev/sdb5
重新创建物理卷成功
root@ubuntu:~# pvcreate /dev/sdb5
Physical volume "/dev/sdb5" successfully created
也可以使用dmsetup remove_all移除所有。
# vgdisplay
--- Volume group ---
VG Name vg_node5
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 6
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 5
Open LV 5
Max PV 0
Cur PV 1
Act PV 1
VG Size 79.51 GiB
PE Size 4.00 MiB
Total PE 20354
Alloc PE / Size 17250 / 67.38 GiB
Free PE / Size 3104 / 12.12 GiB
VG UUID tNuKXc-UdQO-Z8BK-ZtOQ-W93k-pqui-HAxKja
4.对物理卷vg_node5进行扩容
# vgextend vg_node5 /dev/sdb5
Volume group "vg_node5" successfully extended
[root@node5 ~]# vgs
VG #PV #LV #SN Attr VSize VFree
vg_node5 2 5 0 wz--n- 199.47g 132.09g
将逻辑卷vg_node5-data即/data分区扩容到80G
[root@node5 ~]# lvextend -L 80G /dev/mapper/vg_node5-data
Extending logical volume data to 80.00 GiB
Logical volume data successfully resized
重新读取大小
[root@node5 ~]# resize2fs /dev/mapper/vg_node5-data
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/mapper/vg_node5-data is mounted on /data; on-line resizing required
old desc_blocks = 2, new_desc_blocks = 5
Performing an on-line resize of /dev/mapper/vg_node5-data to 20971520 (4k) blocks.
The filesystem on /dev/mapper/vg_node5-data is now 20971520 blocks long.
[root@node5 ~]# df -lh
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_node5-root 20G 479M 18G 3% /
tmpfs 935M 0 935M 0% /dev/shm
/dev/sda1 485M 39M 421M 9% /boot
/dev/mapper/vg_node5-data 79G 184M 75G 1% /data
/dev/mapper/vg_node5-usr 9.7G 1.6G 7.6G 18% /usr
/dev/mapper/vg_node5-web 15G 165M 14G 2% /web