Linux中的LVM之增加容量与删除卷的方法详解

放大lv容量涉及到lvm管理中的命令lvresize，我们先创建一个卷组vg volgroup02，它建立在磁盘/dev/sdc （大小为8g）上。创建逻辑卷lv时，我们故意只使用了一小部分。具体情况如下所示

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代码如下:

[root@localhost ~]# vgdisplay
--- volume group ---
vg name volgroup02
system id
format lvm2
metadata areas 1
metadata sequence no 1
vg access read/write
vg status resizable
max lv 0
cur lv 0
open lv 0
max pv 0
cur pv 1
act pv 1
vg size 7.97 gib
pe size 32.00 mib
total pe 255
alloc pe / size 0 / 0
free pe / size 255 / 7.97 gib
vg uuid setgjx-dobd-uayt-awgn-hkid-hsye-teotis
[root@localhost ~]# lvcreate -l7.97 -n logvol00 volgroup02
rounding up size to full physical extent 32.00 mib
logical volume "logvol00" created
[root@localhost ~]# mkfs -t ext4 /dev/volgroup02/logvol00
mke2fs 1.41.12 (17-may-2010)
filesystem label=
os type: linux
block size=1024 (log=0)
fragment size=1024 (log=0)
stride=0 blocks, stripe width=0 blocks
8192 inodes, 32768 blocks
1638 blocks (5.00%) reserved for the super user
first data block=1
maximum filesystem blocks=33554432
4 block groups
8192 blocks per group, 8192 fragments per group
2048 inodes per group
superblock backups stored on blocks:
8193, 24577

writing inode tables: done
creating journal (4096 blocks): done
writing superblocks and filesystem accounting information: done

this filesystem will be automatically checked every 23 mounts or
180 days, whichever comes first. use tune2fs -c or -i to override.
[root@localhost ~]# cd /
[root@localhost /]# mkdir /u01
[root@localhost /]# mount /dev/volgroup02/logvol00 /u01
[root@localhost /]# vi /etc/fstab

#
# /etc/fstab
# created by anaconda on mon aug 17 15:08:21 2015
#
# accessible filesystems, by reference, are maintained under '/dev/disk'
# see man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
uuid=3440ad55-6486-45ed-876f-e942b08013bf / ext4 defaults 1 1
uuid=d3abb655-db70-4c42-967d-57c421abfda0 /boot ext4 defaults 1 2
uuid=660624ff-335d-42ca-b779-f130a80d9da8 /home ext4 defaults 1 2
uuid=6f534bf0-e486-4937-84ae-ed1221cf34f1 swap swap defaults 0 0
/dev/volgroup02/logvol00 /u01 ext4 defaults 1 1
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0

此时，我们要放大文件系统/u01的大小，那么就需要使用到lvresize 放大lv容量

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代码如下:

[root@localhost ~]# lvscan
active '/dev/volgroup02/logvol00' [32.00 mib] inherit
[root@localhost ~]# lvdisplay /dev/volgroup02/logvol00
--- logical volume ---
lv path /dev/volgroup02/logvol00
lv name logvol00
vg name volgroup02
lv uuid ochwx1-el9p-6c5j-rnuz-2xu5-4215-h3xt5s
lv write access read/write
lv creation host, time localhost.localdomain, 2015-09-01 10:50:10 +0800
lv status available
# open 1
lv size 32.00 mib
current le 1
segments 1
allocation inherit
read ahead sectors auto
- currently set to 256
block device 253:0

[root@localhost ~]# lvresize -l +7.89g /dev/volgroup02/logvol00
rounding size to boundary between physical extents: 7.91 gib
size of logical volume volgroup02/logvol00 changed from 32.00 mib (1 extents) to 7.94 gib (254 extents).
logical volume logvol00 successfully resized

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代码如下:

[root@localhost ~]# resize2fs -p /dev/volgroup02/logvol00
resize2fs 1.41.12 (17-may-2010)
filesystem at /dev/volgroup02/logvol00 is mounted on /u01; on-line resizing required
old desc_blocks = 1, new_desc_blocks = 32
performing an on-line resize of /dev/volgroup02/logvol00 to 8323072 (1k) blocks.
the filesystem on /dev/volgroup02/logvol00 is now 8323072 blocks long.

[root@localhost ~]# df -h
filesystem size used avail use% mounted on
/dev/sda2 27g 6.0g 20g 24% /
tmpfs 5.9g 0 5.9g 0% /dev/shm
/dev/sda1 477m 32m 420m 8% /boot
/dev/sdb1 99g 60m 94g 1% /home
/dev/mapper/volgroup02-logvol00
7.7g 2.7m 7.3g 1% /u01

如果我们此时在虚拟机上将磁盘从8g扩展为10g，那么要如何利用扩展的磁盘空间呢？

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代码如下:

[root@localhost u01]# fdisk -l

disk /dev/sda: 42.9 gb, 42949672960 bytes
64 heads, 32 sectors/track, 40960 cylinders
units = cylinders of 2048 * 512 = 1048576 bytes
sector size (logical/physical): 512 bytes / 512 bytes
i/o size (minimum/optimal): 512 bytes / 512 bytes
disk identifier: 0x000462cf

device boot start end blocks id system
/dev/sda1 * 2 501 512000 83 linux
partition 1 does not end on cylinder boundary.
/dev/sda2 502 28672 28847104 83 linux
partition 2 does not end on cylinder boundary.
/dev/sda3 28673 40960 12582912 82 linux swap / solaris
partition 3 does not end on cylinder boundary.

disk /dev/sdc: 8589 mb, 8589934592 bytes
64 heads, 32 sectors/track, 8192 cylinders
units = cylinders of 2048 * 512 = 1048576 bytes
sector size (logical/physical): 512 bytes / 512 bytes
i/o size (minimum/optimal): 512 bytes / 512 bytes
disk identifier: 0x98c391fe

device boot start end blocks id system
/dev/sdc1 1 8192 8388592 83 linux

disk /dev/sdb: 107.4 gb, 107374182400 bytes
255 heads, 63 sectors/track, 13054 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: 0x0002488e

device boot start end blocks id system
/dev/sdb1 1 13055 104856576 83 linux

disk /dev/mapper/volgroup02-logvol00: 33 mb, 33554432 bytes
255 heads, 63 sectors/track, 4 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

重启过后才能看到/dev/sdc的空间变化情况。


删除物理卷
删除卷lvm管理中的命令vgreduce, pvremove：

   vgreduce：通过删除lvm卷组中的物理卷来减少卷组容量。注意：不能删除lvm卷组中剩余的最后一个物理卷

   pvremove: 用于删除一个存在的物理卷。使用pvremove指令删除物理卷时，它将lvm分区上的物理卷信息删除，使其不再被视为一个物理卷。

在删除物理卷pv之前，必须将服务器的分区信息、卷组信息、物理卷信息、逻辑卷信息都掌握清楚，避免出现失误或误操作。

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代码如下:

[root@localhost ~]# fdisk -l

disk /dev/sda: 128.8 gb, 128849018880 bytes
255 heads, 63 sectors/track, 15665 cylinders
units = cylinders of 16065 * 512 = 8225280 bytes

device boot start end blocks id system
/dev/sda1 * 1 13 104391 83 linux
/dev/sda2 14 10443 83778975 8e linux lvm
/dev/sda3 10444 15665 41945715 83 linux
[root@localhost ~]# vgscan
reading all physical volumes. this may take a while...
found volume group "volgroup00" using metadata type lvm2
[root@localhost ~]# pvscan
pv /dev/sda2 vg volgroup00 lvm2 [79.88 gb / 0 free]
pv /dev/sda3 vg volgroup00 lvm2 [40.00 gb / 40.00 gb free]
total: 2 [119.88 gb] / in use: 2 [119.88 gb] / in no vg: 0 [0 ]
[root@localhost ~]# pvdisplay
--- physical volume ---
pv name /dev/sda2
vg name volgroup00
pv size 79.90 gb / not usable 23.41 mb
allocatable yes (but full)
pe size (kbyte) 32768
total pe 2556
free pe 0
allocated pe 2556
pv uuid ygtb2j-zkjr-mv62-nluq-2dgy-vuut-ccc1lo

--- physical volume ---
pv name /dev/sda3
vg name volgroup00
pv size 40.00 gb / not usable 2.61 mb
allocatable yes
pe size (kbyte) 32768
total pe 1280
free pe 1280
allocated pe 0
pv uuid wsnv13-7j1h-sh8q-hl6k-hpnc-x4wu-gm7lzw

[root@localhost ~]# lvscan
active '/dev/volgroup00/logvol00' [77.91 gb] inherit
active '/dev/volgroup00/logvol01' [1.97 gb] inherit
[root@localhost ~]# lvs
lv vg attr lsize origin snap% move log copy% convert
logvol00 volgroup00 -wi-ao 77.91g
logvol01 volgroup00 -wi-ao 1.97g

vgreduce参数：
-a：如果命令行中没有指定要删除的物理卷，则删除所有的空物理卷；

--removemissing：删除卷组中丢失的物理卷，使卷组恢复正常状态。

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代码如下:

[root@localhost ~]# vgreduce volgroup00 /dev/sda3
removed "/dev/sda3" from volume group "volgroup00"
[root@localhost ~]#

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代码如下:

[root@localhost ~]# pvscan
pv /dev/sda2 vg volgroup00 lvm2 [79.88 gb / 0 free]
pv /dev/sda3 lvm2 [40.00 gb]
total: 2 [119.88 gb] / in use: 1 [79.88 gb] / in no vg: 1 [40.00 gb]
[root@localhost ~]# pvs
pv vg fmt attr psize pfree
/dev/sda2 volgroup00 lvm2 a- 79.88g 0
/dev/sda3 lvm2 a- 40.00g 40.00g
[root@localhost ~]# pvremove /dev/sda3
labels on physical volume "/dev/sda3" successfully wiped
[root@localhost ~]# pvscan
pv /dev/sda2 vg volgroup00 lvm2 [79.88 gb / 0 free]
total: 1 [79.88 gb] / in use: 1 [79.88 gb] / in no vg: 0 [0 ]