DD Linux后默认swap过大的解决办法

1、首先查看Swap位置：swapon -s

root@:~# swapon -s
Filename                                Type            Size    Used    Priority
/dev/sda5                               partition       2094076 0       -1

2、关闭Swap：/sbin/swapoff /dev/sda5

root@:~# /sbin/swapoff /dev/sda5

3、将其删除开机启动：nano /etc/fstab

找到并删除类似于：
UUID=e882xe3f-48xx-4bxx-9cea-01f1af74exxx none            swap    sw              0      $       0

4、保存，reboot 重启，然后删除Swap占用硬盘容量的分区

root@:~# fdisk -l     #查看分区
Disk /dev/sda: 20 GiB, 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
Disklabel type: dos
Disk identifier: 0xb4b4e733

Device     Boot    Start      End  Sectors Size Id Type
/dev/sda1  *        2048 37750783 37748736  18G 83 Linux
/dev/sda2       37752830 41940991  4188162   2G  5 Extended
/dev/sda5       37752832 41940991  4188160   2G 82 Linux swap / Solaris

root@:~# fdisk /dev/sda     #此处"/dev/sda" 根据你的显示进行修改
Welcome to fdisk (util-linux 2.29.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Command (m for help):d     #删除
Partition number (1,2,5, default 5):5     #序号为"5"的分区
Partition 5 has been deleted.

Command (m for help):d     #删除
Partition number (1,2, default 2): 2     #序号为"2"的分区
Partition 2 has been deleted.

Command (m for help):w     #保存
The partition table has been altered.
Calling ioctl() to re-read partition table.
Re-reading the partition table failed.: 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).

5、将删除的空间扩容至主空间

安装growpart软件

# centos：
yum install -y cloud-utils-growpart
# Debian：
apt install -y cloud-guest-utils

* 如果你硬盘是GPT格式的请安装以下软件，MBR格式请忽略。——怎么查看硬盘格式是GPT，还是MBR？这个见本文最下方。

# centos：
yum install gdisk -y
# Debian：
apt-get install gdisk -y

root@:~# growpart /dev/sda 1
failed [pt_update:1] pt_update /dev/sda 1
partx: /dev/sda: error updating partition 1
FAILED: pt_resize failed

root@:~# resize2fs /dev/sda1
resize2fs 1.43.4 (31-Jan-2017)
The filesystem is already 4718592 (4k) blocks long.  Nothing to do!

root@:~# df -h
Filesystem      Size  Used Avail Use% Mounted on
udev            992M     0  992M   0% /dev
tmpfs           201M  2.9M  198M   2% /run
/dev/sda1        18G  742M   16G   5% /
tmpfs          1003M     0 1003M   0% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs          1003M     0 1003M   0% /sys/fs/cgroup
tmpfs           201M     0  201M   0% /run/user/0

root@:~# resize2fs /dev/sda1resize2fs 1.43.4 (31-Jan-2017)
Filesystem at /dev/sda1 is mounted on /; on-line resizing required
old_desc_blocks = 3, new_desc_blocks = 3
The filesystem on /dev/vda1 is now 5242619 (4k) blocks long.root@:~# df -hFilesystem      Size  Used Avail Use% Mounted on
udev            992M     0  992M   0% /dev
tmpfs           201M  2.9M  198M   2% /run
/dev/sda1        20G  742M   18G   4% /
tmpfs          1003M     0 1003M   0% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs          1003M     0 1003M   0% /sys/fs/cgroup
tmpfs           201M     0  201M   0% /run/user/0

完成！白花花的2G容量回归了主分区上。

6、如果再次需要swap的话，可以运行一键添加swap脚本，这个脚本可以很轻松的添加/删除swap，而且添加的swap位于主分区上可以随时拆装。

一键添加/删除Swap虚拟内存（不支持open vz） ：

wget https://www.moerats.com/usr/shell/swap.sh && bash swap.sh

常见问题：

* 怎么查看硬盘格式是GPT，还是MBR？

方法一：

fdisk -l

方法二：

parted -l