首先查看是否还有未分配的磁盘空间，有则直接热扩容就行。没有的话参照下面：
首先在虚拟机的编辑里面添加一块新的硬盘，选择thin，模式。
然后重启centos
小于2T的扩容使用fdisk就行
fdisk -l 查看新加进去的磁盘 给磁盘分区 [root@localhost ~]# fdisk /dev/sdb 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. Device does not contain a recognized partition table Building a new DOS disklabel with disk identifier 0x95f32263. Command (m for help): n Partition type: p primary (0 primary, 0 extended, 4 free) e extended Select (default p): p Partition number (1-4, default 1): First sector (2048-41943039, default 2048): Using default value 2048 Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): Using default value 41943039 Partition 1 of type Linux and of size 20 GiB is set Command (m for help): t Selected partition 1 Hex code (type L to list all codes): L 0 Empty 24 NEC DOS 81 Minix / old Lin bf Solaris 1 FAT12 27 Hidden NTFS Win 82 Linux swap / So c1 DRDOS/sec (FAT- 2 XENIX root 39 Plan 9 83 Linux c4 DRDOS/sec (FAT- 3 XENIX usr 3c PartitionMagic 84 OS/2 hidden C: c6 DRDOS/sec (FAT- 4 FAT16 <32M 40 Venix 80286 85 Linux extended c7 Syrinx 5 Extended 41 PPC PReP Boot 86 NTFS volume set da Non-FS data 6 FAT16 42 SFS 87 NTFS volume set db CP/M / CTOS / . 7 HPFS/NTFS/exFAT 4d QNX4.x 88 Linux plaintext de Dell Utility 8 AIX 4e QNX4.x 2nd part 8e Linux LVM df BootIt 9 AIX bootable 4f QNX4.x 3rd part 93 Amoeba e1 DOS access a OS/2 Boot Manag 50 OnTrack DM 94 Amoeba BBT e3 DOS R/O b W95 FAT32 51 OnTrack DM6 Aux 9f BSD/OS e4 SpeedStor c W95 FAT32 (LBA) 52 CP/M a0 IBM Thinkpad hi eb BeOS fs e W95 FAT16 (LBA) 53 OnTrack DM6 Aux a5 FreeBSD ee GPT f W95 Ext'd (LBA) 54 OnTrackDM6 a6 OpenBSD ef EFI (FAT-12/16/ 10 OPUS 55 EZ-Drive a7 NeXTSTEP f0 Linux/PA-RISC b 11 Hidden FAT12 56 Golden Bow a8 Darwin UFS f1 SpeedStor 12 Compaq diagnost 5c Priam Edisk a9 NetBSD f4 SpeedStor 14 Hidden FAT16 <3 61 SpeedStor ab Darwin boot f2 DOS secondary 16 Hidden FAT16 63 GNU HURD or Sys af HFS / HFS+ fb VMware VMFS 17 Hidden HPFS/NTF 64 Novell Netware b7 BSDI fs fc VMware VMKCORE 18 AST SmartSleep 65 Novell Netware b8 BSDI swap fd Linux raid auto 1b Hidden W95 FAT3 70 DiskSecure Mult bb Boot Wizard hid fe LANstep 1c Hidden W95 FAT3 75 PC/IX be Solaris boot ff BBT 1e Hidden W95 FAT1 80 Old Minix Hex code (type L to list all codes): 8e Changed type of partition 'Linux' to 'Linux LVM' Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. Syncing disks.
mkfs.xfs /dev/sda3 进行格式化
指令：mkfs.xfs /dev/sda3
使用 lvm扩充分区
指令： lvm
pvcreate /dev/sda3
使用pvdisplay查看当前卷信息，发现/dev/sda2的VG Name是VolGroup，因此需要将/dev/sda3加入到VolGroup卷里面去。
指令： pvdisplay
将/dev/sda3加入到VolGroup卷里面去
指令： vgextend VolGroup /dev/sda3
lvextend -L +39.9G /dev/mapper/VolGroup-lv_home
最后要调整逻辑分区大小，才能看到新的空间
指令： resize2fs /dev/mapper/VolGroup-lv_home
我是xfs的。。所以用xfs_growfs /dev/mapper/centos-home
注意这块可能有如下报错：
[root@backup binlog]# resize2fs /dev/mapper/centos-home
resize2fs 1.42.9 (28-Dec-2013)
resize2fs: Bad magic number in super-block 当尝试打开 /dev/mapper/centos-home 时
找不到有效的文件系统超级块.
确认文件系统是xfs:
[root@backup binlog]# cat /etc/fstab | grep centos-home
/dev/mapper/centos-home /home xfs defaults 0 0
xfs用以下命令来扩磁盘空间:
[root@backup binlog]# xfs_growfs /dev/mapper/centos-home
meta-data=/dev/mapper/centos-home isize=256 agcount=6, agsize=118277632 blks
= sectsz=4096 attr=2, projid32bit=1
= crc=0 finobt=0
data = bsize=4096 blocks=709040128, imaxpct=5
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=0
log =internal bsize=4096 blocks=231011, version=2
= sectsz=4096 sunit=1 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 709040128 to 715331584
11. 最后用df –lh查看空间已经变更了。ok！