Linux系统LVM扩容一个分区相对于Windows来说没有那么直观，但是熟悉命令后，扩容起来也是蛮方便的。
扩容场景如下：
1 [root@rhel06 ~]# df -Th2 Filesystem Type Size Used Avail Use% Mounted on
3 /dev/sda2 ext4 9.9G 2.2G 7.3G 23% /
4 tmpfs tmpfs 491M 0 491M 0% /dev/shm
5 /dev/sda1 ext4 194M 29M 155M 16% /boot
6 /dev/sr0 iso9660 3.6G 3.6G 0 100% /mnt
7 /dev/mapper/VG001-lv1 ext4 2.0G 67M 1.9G 4% /lv1
现有一个lvm分区lv1容量2G，希望扩容此分区空间
1 [root@rhel06 home]# cat /proc/partitions 2 major minor #blocks name 3 4 8 0 20971520 sda
5 8 1 204800 sda1
6 8 2 10485760 sda2
7 8 3 2097152 sda3
8 8 4 1 sda4
9 8 5 2103487 sda5
10 253 0 2097152 dm-0
查看partitions 获取当前分区情况和磁盘总空间情况。需要计算20971520-204800-10485760-2097152-2103487-1=6080320，约6G的未使用空间。（dm-0是一个lv分区）
当然使用这种手动方式获取未分区空间太过麻烦。可以用这个shell来完成大量的计算
1 [root@rhel06 home]# cat sda.sh 2#!/bin/bash 3 total=$(grep ‘sda$‘ /proc/partitions |awk ‘{print $3}‘);
4 used=0
5for i in $(grep ‘sda[[:digit:]]+$‘ /proc/partitions |awk ‘{print $3}‘ |xargs)
6do
7 used=$(( used + i ));
8done
9 echo $((( total - used ) / 1024 )) "MB"10 [root@rhel06 home]# ./sda.sh 115937 MB
接下来执行具体的分区步骤：
一、划分一个新分区并格式化
1 [root@rhel06 ~]# fdisk /dev/sda 2 3 Command (m for help): p
4 5 Disk /dev/sda: 21.5 GB, 21474836480 bytes
6 255 heads, 63 sectors/track, 2610 cylinders
7 Units = cylinders of 16065 * 512 = 8225280 bytes
8 Sector size (logical/physical): 512 bytes / 512 bytes
9 I/O size (minimum/optimal): 512 bytes / 512 bytes
10 Disk identifier: 0x00029f55
1112 Device Boot Start End Blocks Id System
13 /dev/sda1 * 1 26 204800 83 Linux
14 Partition 1 does not end on cylinder boundary.
15 /dev/sda2 26 1332 10485760 83 Linux
16 /dev/sda3 1332 1593 2097152 82 Linux swap / Solaris
17 /dev/sda4 1593 2610 8176089 5 Extended
18 /dev/sda5 1593 1854 2103487+ 8e Linux LVM
1920 Command (m for help): n #新建分区，由于我已新建了四个分区（主分区和逻辑分区），所以这里只能新建扩展分区，并没有出现分区类型选项
21 First cylinder (1855-2610, default 1855): #开始点，直接回车即可
22 Using default value 1855
23 Last cylinder, +cylinders or +size{K,M,G} (1855-2610, default 2610): +2G #+2G，划分一个2G的新分区
2425 Command (m for help): p
2627 Disk /dev/sda: 21.5 GB, 21474836480 bytes
28 255 heads, 63 sectors/track, 2610 cylinders
29 Units = cylinders of 16065 * 512 = 8225280 bytes
30 Sector size (logical/physical): 512 bytes / 512 bytes
31 I/O size (minimum/optimal): 512 bytes / 512 bytes
32 Disk identifier: 0x00029f55
3334 Device Boot Start End Blocks Id System
35 /dev/sda1 * 1 26 204800 83 Linux
36 Partition 1 does not end on cylinder boundary.
37 /dev/sda2 26 1332 10485760 83 Linux
38 /dev/sda3 1332 1593 2097152 82 Linux swap / Solaris
39 /dev/sda4 1593 2610 8176089 5 Extended
40 /dev/sda5 1593 1854 2103487+ 8e Linux LVM
41 /dev/sda6 1855 2116 2104483+ 83 Linux
4243 Command (m for help): w #保存退出
1 [root@rhel06 ~]# partprobe #不要忘了刷新分区表，虚拟机还是需要重启才能刷新。
1 [root@rhel06 ~]# mkfs.ext4 /dev/sda6 #格式化
二、转换sda6分区为pv
1 [root@rhel06 ~]# pvcreate /dev/sda6 #转换sda6分区 2 dev_is_mpath: failed to get device for 8:6
3 Physical volume "/dev/sda6" successfully created
4 [root@rhel06 ~]# pvdisplay #查看系统所有pv，这里sda6已成功转换 5 --- Physical volume ---
6 PV Name /dev/sda5
7 VG Name VG001
8 PV Size 2.01 GiB / not usable 2.19 MiB
9 Allocatable yes
10 PE Size 4.00 MiB
11 Total PE 513
12 Free PE 1
13 Allocated PE 512
14 PV UUID dSHFLX-9Lui-0ZDb-6J2g-pp6A-azuX-vg5yGV
1516"/dev/sda6"is a new physical volume of "2.01 GiB"17 --- NEW Physical volume ---
18 PV Name /dev/sda6
19 VG Name
20 PV Size 2.01 GiB
21 Allocatable NO
22 PE Size 0
23 Total PE 0
24 Free PE 0
25 Allocated PE 0
26 PV UUID TEGKht-876S-8MMd-vWkX-rjeI-4UqG-JqRsT2
三、添加新pv到vg
1 [root@rhel06 ~]# vgdisplay |grep Name #查看当前vg名称 2 VG Name VG001
3 [root@rhel06 ~]# vgextend VG001 /dev/sda6 #添加“sda6”pv到此vg 4 Volume group "VG001" successfully extended
5 [root@rhel06 ~]# vgdisplay #查看vg详情，可以看到vg已经扩容到4g 6 --- Volume group ---
7 VG Name VG001
8 System ID
9 Format lvm2
10 Metadata Areas 2
11 Metadata Sequence No 3
12 VG Access read/write
13 VG Status resizable
14 MAX LV 0
15 Cur LV 1
16 Open LV 1
17 Max PV 0
18 Cur PV 2
19 Act PV 2
20 VG Size 4.01 GiB
21 PE Size 4.00 MiB
22 Total PE 1026
23 Alloc PE / Size 512 / 2.00 GiB
24 Free PE / Size 514 / 2.01 GiB
25 VG UUID qG18Fp-agAP-gaTp-0crS-Ughm-UilM-2ZftQt
四、调整lv1容量
1 [root@rhel06 ~]# lvextend -L 4G /dev/VG001/lv1 #调整lv1分区容量为4G，原来是2G2 Extending logical volume lv1 to 4.00 GiB
3 Logical volume lv1 successfully resized
4 [root@rhel06 ~]# resize2fs /dev/VG001/lv1 #执行重设大小，对当前lv1有效5 resize2fs 1.41.12 (17-May-2010)
6 Filesystem at /dev/VG001/lv1 is mounted on /lv1; on-line resizing required
7 old desc_blocks = 1, new_desc_blocks = 1
8 Performing an on-line resize of /dev/VG001/lv1 to 1048576 (4k) blocks.
9 The filesystem on /dev/VG001/lv1 is now 1048576 blocks long.
五、到此设置已完成，df命令查看已扩容到4G
1 [root@rhel06 ~]# df -h2 Filesystem Size Used Avail Use% Mounted on
3 /dev/sda2 9.9G 2.2G 7.3G 23% /
4 tmpfs 491M 0 491M 0% /dev/shm
5 /dev/sda1 194M 29M 155M 16% /boot
6 /dev/sr0 3.6G 3.6G 0 100% /mnt
7 /dev/mapper/VG001-lv1 4.0G 68M 3.7G 2% /lv1
问题1：执行partprobe刷新分区表时会出现以下报错：
[root@rhel06 ~]# partprobe Warning: WARNING: the kernel failed to re-read the partition table on /dev/sda (设备或资源忙). As a result, it may not reflect all of your changes until after reboot.
这个问题貌似只存在于虚拟机上面，物理机上并没有发现这个问题。重启虚拟机即可。
问题2：fdisk可以查看到sda5分区，但是使用mkfs格式化是提示“没有这个文件或目录”，那是分区表没有刷新或者刷新失败，刷新步骤可参考上一个问题。
1
Device Boot Start End Blocks Id System
2 /dev/sda1 * 1 26 204800 83 Linux
3 Partition 1 does not end on cylinder boundary.
4 /dev/sda2 26 1332 10485760 83 Linux
5 /dev/sda3 1332 1593 2097152 82 Linux swap / Solaris
6 /dev/sda4 1593 2610 8176089 5 Extended
7 /dev/sda5 1593 1854 2103487+ 83 Linux
8 [root@rhel06 ~]# mkfs.ext4 /dev/sda5 9 mke2fs 1.41.12 (17-May-2010)
10 无法对 /dev/sda5 进行 stat 调用 --- 没有那个文件或目录
原文：http://www.cnblogs.com/tail-f/p/6143085.html
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