一）虚拟机分区扩容
参考转载地址：https://segmentfault.com/a/1190000007645451 (亲测有效)
VirtualBox中安装了CentOS 7，给同事用来做kafka和zookeeper测试服务器。昨晚kafka意外终止，看了日志发现是/root只分配了1GiB大小，已接近饱和。开始bing，总结一下步骤：
列出各分区使用情况：
# df -Th
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/centos-root xfs 997M 994M 2.9M 100% /
devtmpfs devtmpfs 915M 0 915M 0% /dev
tmpfs tmpfs 921M 0 921M 0% /dev/shm
tmpfs tmpfs 921M 17M 905M 2% /run
tmpfs tmpfs 921M 0 921M 0% /sys/fs/cgroup
/dev/mapper/centos-usr xfs 4.9G 1.6G 3.4G 33% /usr
/dev/sda1 xfs 97M 66M 31M 69% /boot
/dev/mapper/centos-var xfs 2.4G 473M 1.9G 21% /var
可以看见 /dev/mapper/centos-root 已经使用了100%，我们准备为它扩容。
在VirtualBox中添加一块新的虚拟磁盘：
先关闭操作系统。在VirtualBox中选中当前VM，设置->存储->控制器->SATA控制器，点击图标“添加虚拟硬盘”，新建一个虚拟硬盘。我增加了一块3GiB大小的虚拟磁盘，保存后再次启动虚拟机。
创建新分区
先看一下现有磁盘情况：
# fdisk -l
Disk /dev/sda: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000940ec
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 206847 102400 83 Linux
/dev/sda2 206848 41943039 20868096 8e Linux LVM
Disk /dev/sdb: 3221 MB, 3221225472 bytes, 6291456 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/centos-swap: 2097 MB, 2097152000 bytes, 4096000 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/centos-usr: 5242 MB, 5242880000 bytes, 10240000 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/centos-root: 1048 MB, 1048576000 bytes, 2048000 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
...
已经可以看到新磁盘/dev/sdb。
对新磁盘进行分区
# fdisk /dev/sdb
在fdisk的交互模式中，依次输入：
n //创建新分区
p //创建主分区
<回车> //默认分区编号
<回车> //默认起始扇区位置。
<回车> //默认结束扇区位置。
w //写入分区表
这样就把整个磁盘分成了一个区。
再看一下现有磁盘情况
# partprobe //强制内核读取磁盘分区表，不然下面命令将不能显示出新的分区
# fdisk -l
Device Boot Start End Blocks Id System
/dev/sdb1 2048 6291455 3144704 83 Linux
将新分区用于扩展/root
先看一下卷分组：
# vgdisplay -v
Finding all volume groups
Finding volume group "centos"
--- Volume group ---
VG Name centos //记录下卷分组名，以待后用
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 19.90 GiB
PE Size 4.00 MiB
Total PE 5094
Alloc PE / Size 5093 / 19.89 GiB
Free PE / Size 1 / 4.00 MiB
VG UUID vtJL08-7Jxi-5IqK-3fUg-Pben-682a-wiv2GL
--- Logical volume ---
LV Path /dev/centos/root //待扩展的分区，记录待用
LV Name root
VG Name centos
LV UUID ZWTgoT-AMWs-g54v-dZA1-NQUj-mqGa-8tmr4U
LV Write Access read/write
LV Creation host, time localhost, 2016-07-03 21:59:31 -0400
LV Status available
# open 1
LV Size 1000.00 MiB
Current LE 250
Segments 1
Allocation inherit
Read ahead sectors auto
currently set to 256
Block device 253:2
...
--- Physical volumes ---
PV Name /dev/sda2
PV UUID fiVH1e-lwfi-63Lr-oIlK-GDZI-dcuZ-T04VlC
PV Status allocatable
Total PE / Free PE 5094 / 1
...
为之前新增的分区创建物理卷
# pvcreate /dev/sdb1
查看结果：
# pvdisplay
--- Physical volume ---
PV Name /dev/sda2
VG Name centos
PV Size 19.90 GiB / not usable 3.00 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 5094
Free PE 1
Allocated PE 5093
PV UUID fiVH1e-lwfi-63Lr-oIlK-GDZI-dcuZ-T04VlC
"/dev/sdb1" is a new physical volume of "3.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdb1
VG Name
PV Size 3.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID VGXSAn-UiZ0-Fy40-eQxb-53xA-5hZM-3eGPg0
扩展卷分组,"centos"是vgdisplay命令查到的卷分组名
# vgextend centos /dev/sdb1
查看扩展结果，可用下面命令：
# lvdisplay
下面扩展逻辑卷/dev/centos/root
# lvextend -L +3G /dev/centos/root
再运行下面命令将文件系统扩大：
# xfs_growfs /dev/centos/root
再运行下面命令查看扩展后结果：
# df -Th
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/centos-root xfs 4.0G 995M 3.1G 25% /
devtmpfs devtmpfs 915M 0 915M 0% /dev
tmpfs tmpfs 921M 0 921M 0% /dev/shm
tmpfs tmpfs 921M 8.4M 913M 1% /run
tmpfs tmpfs 921M 0 921M 0% /sys/fs/cgroup
/dev/mapper/centos-usr xfs 4.9G 1.6G 3.4G 33% /usr
/dev/mapper/centos-home xfs 9.8G 391M 9.4G 4% /home
/dev/mapper/centos-var xfs 2.4G 469M 1.9G 20% /var
/dev/sda1 xfs 97M 66M 31M 69% /boot
二）物理机分区容量调整
centos7默认xfs为文件系统， xfs因为只能增大，不能减少，所以需要调整/home，增大/,需要安装xfsdump,步骤如下，做个记录：
# yum install -y xfsdump
查看现有分区情况： # df -h
/dev/mapper/cl_hadoop-root 50G 3.1G 47G 7% /
devtmpfs 7.7G 0 7.7G 0% /dev
tmpfs 7.8G 0 7.8G 0% /dev/shm
tmpfs 7.8G 8.4M 7.8G 1% /run
tmpfs 7.8G 0 7.8G 0% /sys/fs/cgroup
/dev/mapper/cl_hadoop-home 142G 424M 141G 1% /home
/dev/vda1 1014M 139M 876M 14% /boot
tmpfs 1.6G 0 1.6G 0% /run/user/0
需要减少/home目录，增大/目录，先备份一下/home目录： # xfsdump -l 0 -L home -M home -f /opt/home.xfsdump /home
卸载/home目录： # umount /home
调整/home目录到5G: # lvreduce -L 5G /dev/mapper/cl_hadoop-home
WARNING: Reducing active logical volume to 5.00 GiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce cl_hadoop/home? [y/n]: y
Size of logical volume cl_hadoop/home changed from 141.18 GiB (36142 extents) to 5.00 GiB (1280 extents).
Logical volume cl_hadoop/home successfully resized.
增大/目录： # lvextend -l +100%FREE /dev/cl_hadoop/root
Size of logical volume cl_hadoop/root changed from 50.00 GiB (12800 extents) to 186.18 GiB (47663 extents).
Logical volume cl_hadoop/root successfully resized.
延伸/目录空间： # xfs_growfs /dev/cl_hadoop/root
meta-data=/dev/mapper/cl_hadoop-root isize=512 agcount=4, agsize=3276800 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=13107200, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=6400, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 13107200 to 48806912
重新格式化home分区： # mkfs.xfs -f /dev/mapper/cl_hadoop-home
meta-data=/dev/mapper/cl_hadoop-home isize=512 agcount=4, agsize=327680 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=1310720, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
挂在home目录： # mount /home
还原备份文件到/home目录： # xfsrestore -f /opt/home.xfsdump /home
xfsrestore: using file dump (drive_simple) strategy
xfsrestore: version 3.1.4 (dump format 3.0) - type ^C for status and control
xfsrestore: searching media for dump
xfsrestore: examining media file 0
xfsrestore: dump description:
xfsrestore: hostname: hadoop
xfsrestore: mount point: /home
xfsrestore: volume: /dev/mapper/cl_hadoop-home
xfsrestore: session time: Sat Aug 5 19:49:06 2017
xfsrestore: level: 0
xfsrestore: session label: "home"
xfsrestore: media label: "home"
xfsrestore: file system id: f716ff51-3556-491a-a324-de943e23277b
xfsrestore: session id: 47a21c87-c24e-47fe-a501-cd5f5565c6c5
xfsrestore: media id: 553706c1-917a-440a-9cd8-31779fa17089
xfsrestore: using online session inventory
xfsrestore: searching media for directory dump
xfsrestore: reading directories
xfsrestore: 4 directories and 14 entries processed
xfsrestore: directory post-processing
xfsrestore: restoring non-directory files
xfsrestore: restore complete: 1 seconds elapsed
xfsrestore: Restore Summary:
xfsrestore: stream 0 /opt/home.xfsdump OK (success)
xfsrestore: Restore Status: SUCCESS
至此，完整容量调整！