原文链接：https://github.com/imcczy/imcczy.github.io/blob/master/_posts/2014-12-07-how-to-expand-the-root-filesystem-in-vmware.md
年代久远，谨慎尝试
虚拟机用着用着空间就不够了，google了一篇文章，试了一下，有用，征得作者同意，翻译了下。删了一些无关的东西。
注：
作者输入命令时都用“sudo bash”，用sudo或者su就可以了。
再注：
涉及到磁盘分区表删除，最好先备份整个虚拟机！
检查文件系统：
cruz@ubuntu:~$ sudo bash
[sudo] password for cruz:
root@ubuntu:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 9.0G 2.7G 5.9G 32% /
udev 488M 4.0K 488M 1% /dev
tmpfs 199M 800K 198M 1% /run
none 5.0M 0 5.0M 0% /run/lock
none 497M 76K 496M 1% /run/shm
root@ubuntu:~#
检查磁盘分区表：
root@ubuntu:~# fdisk -l /dev/sda
Disk /dev/sda: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders, total 20971520 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 identifier: 0x00001dec
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 18874367 9436160 83 Linux
/dev/sda2 18876414 20969471 1046529 5 Extended
/dev/sda5 18876416 20969471 1046528 82 Linux swap / Solaris
root@ubuntu:~#
记住上面显示的交换分区大小（Blocks的数目），这里就是1046528。如果交换分区和根目录不在一个磁盘(比如/dev/sdb），就不要记了。在本文，交换分区在/dev/sda，需要重新分区。
先关闭linux：
root@ubuntu:~# shutdown -h now
在虚拟机设置，硬盘，实用工具下选择扩展。扩展虚拟机的最大磁盘大小，这里将磁盘设置为15G，然后重启。
重新设置分区表要删除所有的旧分区、关闭系统的swap:
cruz@ubuntu:~$ sudo bash
[sudo] password for cruz:
root@ubuntu:~# free -m
total used free shared buffers cached
Mem: 992 924 67 0 43 426
-/+ buffers/cache: 454 537
Swap: 1021 0 1021
root@ubuntu:~# swapoff -a
root@ubuntu:~# free -m
total used free shared buffers cached
Mem: 992 924 67 0 43 426
-/+ buffers/cache: 454 537
Swap: 0 0 0
root@ubuntu:~#
接下来的步骤会删除/dev/sda1和/dev/sda2，一定要记住分区表的起始位置，这里是2048！
root@ubuntu:~# fdisk /dev/sda
Command (m for help): p
Disk /dev/sda: 16.1 GB, 16106127360 bytes
255 heads, 63 sectors/track, 1958 cylinders, total 31457280 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 identifier: 0x00001dec
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 18874367 9436160 83 Linux
/dev/sda2 18876414 20969471 1046529 5 Extended
/dev/sda5 18876416 20969471 1046528 82 Linux swap / Solaris
Command (m for help): d
Partition number (1-5): 1
Command (m for help): d
Partition number (1-5): 2
Command (m for help): p
Disk /dev/sda: 16.1 GB, 16106127360 bytes
255 heads, 63 sectors/track, 1958 cylinders, total 31457280 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 identifier: 0x00001dec
Device Boot Start End Blocks Id System
Command (m for help):
不要退出fdisk，接着创建新分区
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): 1
First sector (2048-31457279, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-31457279, default 31457279): 30410751
Command (m for help): n
Partition type:
p primary (1 primary, 0 extended, 3 free)
e extended
Select (default p): p
Partition number (1-4, default 2):
Using default value 2
First sector (30410752-31457279, default 30410752):
Using default value 30410752
Last sector, +sectors or +size{K,M,G} (30410752-31457279, default 31457279):
Using default value 31457279
注意记得创建交换分区，大小别搞错，这里是1046528（31457279-30410571=1046528），即要留一部分block用于创建swap。修改sda2的分区类型为82，即交换分区。
Command (m for help): p
Disk /dev/sda: 16.1 GB, 16106127360 bytes
255 heads, 63 sectors/track, 1958 cylinders, total 31457280 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 identifier: 0x00001dec
Device Boot Start End Blocks Id System
/dev/sda1 2048 30410751 15204352 83 Linux
/dev/sda2 30410752 31457279 523264 83 Linux
Command (m for help): t
Partition number (1-4): 2
Hex code (type L to list codes): 82
Changed system type of partition 2 to 82 (Linux swap / Solaris)
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.
root@ubuntu:~#
重启虚拟机：
root@ubuntu:~# shutdown -r now
交换分区挂载需要UUID标识符。创建新的交换分区不会匹配旧的UUID，导致重启无法挂载swap分区。这里主要有两种解决方法：在/etc/fstab里写入新的UUID，或者直接将旧的UUID覆盖在新分区上，这里选择后者。
awk命令用来显示旧的UUID，dd命令确保分区没数据。
cruz@ubuntu:~$ sudo bash
[sudo] password for cruz:
root@ubuntu:~# awk '/swap/ { print $1 }' /etc/fstab
#
UUID=8bb62351-4436-47df-92fe-af2865f03461
root@ubuntu:~# swapoff -a
root@ubuntu:~# free -m
total used free shared buffers cached
Mem: 992 695 296 0 23 325
-/+ buffers/cache: 346 645
Swap: 0 0 0
root@ubuntu:~# dd if=/dev/zero of=/dev/sda2
dd: writing to '/dev/sda2': No space left on device
1046529+0 records in
1046528+0 records out
535822336 bytes (536 MB) copied, 11.9388 s, 44.9 MB/s
root@ubuntu:~# mkswap -U 8bb62351-4436-47df-92fe-af2865f03461 /dev/sda2
Setting up swapspace version 1, size = 523260 KiB
no label, UUID=8bb62351-4436-47df-92fe-af2865f03461
root@ubuntu:~# swapon -a
root@ubuntu:~# free -m
total used free shared buffers cached
Mem: 992 693 298 0 23 325
-/+ buffers/cache: 345 646
Swap: 510 7 503
root@ubuntu:~#
最后，调整分区大小：
root@ubuntu:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 9.0G 2.8G 5.8G 33% /
udev 488M 4.0K 488M 1% /dev
tmpfs 199M 788K 198M 1% /run
none 5.0M 0 5.0M 0% /run/lock
none 497M 200K 496M 1% /run/shm
root@ubuntu:~# resize2fs /dev/sda1
resize2fs 1.42 (29-Nov-2011)
Filesystem at /dev/sda1 is mounted on /; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 1
Performing an on-line resize of /dev/sda1 to 3801088 (4k) blocks.
The filesystem on /dev/sda1 is now 3801088 blocks long.
root@ubuntu:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 15G 2.8G 11G 21% /
udev 488M 4.0K 488M 1% /dev
tmpfs 199M 788K 198M 1% /run
none 5.0M 0 5.0M 0% /run/lock
none 497M 200K 496M 1% /run/shm
root@ubuntu:~#