簡介
CentOS7虛擬機原硬盤空間只分配了10GB，需要擴容到20GB。
環境：VMware 10
VMware分配空間
選中虛擬機->虛擬機設置->硬盤->實用工具->擴展->設置最大磁盤大小->點擊擴展
這裏寫圖片描述
CentOS7內部分配
可以參考：http://jingyan.baidu.com/article/54b6b9c0fc8b0b2d583b47c6.html
http://blog.csdn.net/Wang_Xin_SH/article/details/77872885
查看當前磁盤空間，/dev/mapper/cl-root硬盤空間只有8GB，打算擴容：
df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/cl-root 8.0G 3.8G 4.3G 47% /
devtmpfs 482M 0 482M 0% /dev
tmpfs 493M 0 493M 0% /dev/shm
tmpfs 493M 6.7M 486M 2% /run
tmpfs 493M 0 493M 0% /sys/fs/cgroup
/dev/sda1 1014M 184M 831M 19% /boot
tmpfs 99M 0 99M 0% /run/user/0
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對新增的硬盤空間做新增分區（硬盤數沒有增加，增加的是空間）
fdisk /dev/sda
Welcome to fdisk (util-linux 2.23.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): n
Partition type:
p primary (2 primary, 0 extended, 2 free)
e extended
Select (default p): p
Partition number (3,4, default 3): 3
First sector (20971520-41943039, default 20971520):
Using default value 20971520
Last sector, +sectors or +size{K,M,G} (20971520-41943039, default 41943039):
Using default value 41943039
Partition 3 of type Linux and of size 10 GiB is set
Command (m for help): t
Partition number (1-3, default 3): 3
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'
Command (m for help): p
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: 0x000bc924
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 2099199 1048576 83 Linux
/dev/sda2 2099200 20971519 9436160 8e Linux LVM
/dev/sda3 20971520 41943039 10485760 8e Linux LVM
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.
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重啓系統 reboot
查看當前分區類型，本例類型爲xfs
df -T /dev/sda1
Filesystem Type 1K-blocks Used Available Use% Mounted on
/dev/sda1 xfs 1038336 188240 850096 19% /boot
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在新磁盤上創建xfs文件系統
mkfs.xfs /dev/sda3
meta-data=/dev/sda3 isize=512 agcount=4, agsize=655360 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=2621440, 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
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創建PV
pvcreate /dev/sda3
WARNING: xfs signature detected on /dev/sda3 at offset 0. Wipe it? [y/n]: y
Wiping xfs signature on /dev/sda3.
Physical volume "/dev/sda3" successfully created.
pvdisplay
--- Physical volume ---
PV Name /dev/sda2
VG Name cl
PV Size 9.00 GiB / not usable 3.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 2303
Free PE 0
Allocated PE 2303
PV UUID MlRwjY-TmVF-H8PV-heSz-ALGL-Q7sp-jFU6Al
"/dev/sda3" is a new physical volume of "10.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sda3
VG Name
PV Size 10.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID 0hmgH0-0wVg-jWUW-65WX-1TYb-sUGH-6jF1qm
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PV加入VG，vgextend後接VG Name，本例中爲cl
vgdisplay
--- Volume group ---
VG Name cl
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size 9.00 GiB
PE Size 4.00 MiB
Total PE 2303
Alloc PE / Size 2303 / 9.00 GiB
Free PE / Size 0 / 0
VG UUID dYdb4l-wMUh-e2xv-WiaJ-Oa52-NvdF-s5ICJC
vgextend cl /dev/sda3
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VG加入LV
lvextend -l +2559 /dev/cl/root
Size of logical volume cl/root changed from 8.00 GiB (2047 extents) to 17.99 GiB (4606 extents).
Logical volume cl/root successfully resized.
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後兩個參數“+2559”和“/dev/cl/root”來源詳解：
“+2559”來自於vgdisplay命令的Free PE/Size字段
vgdisplay
--- Volume group ---
VG Name cl
...
VG Size 18.99 GiB
PE Size 4.00 MiB
Total PE 4862
Alloc PE / Size 2303 / 9.00 GiB
Free PE / Size 2559 / 10.00 GiB
VG UUID dYdb4l-wMUh-e2xv-WiaJ-Oa52-NvdF-s5ICJC
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“/dev/cl/root”來自於lvdisplay命令的LV Path字段。
lvdisplay
...
--- Logical volume ---
LV Path /dev/cl/root
...
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調整文件系統大小，本例中是xfs文件系統使用xfs_growfs命令調整，若其他文件系統，如ext4使用resize2fs命令，注意區分。
xfs_growfs /dev/cl/root
meta-data=/dev/mapper/cl-root isize=512 agcount=4, agsize=524032 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=2096128, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 2096128 to 4716544
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結果
/dev/mapper/cl-root從8G增加到了18G
df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/cl-root 18G 3.8G 15G 21% /
devtmpfs 482M 0 482M 0% /dev
tmpfs 493M 0 493M 0% /dev/shm
tmpfs 493M 6.7M 486M 2% /run
tmpfs 493M 0 493M 0% /sys/fs/cgroup
/dev/sda1 1014M 184M 831M 19% /boot
tmpfs 99M 0 99M 0% /run/user/0