经常爆内存，导致很多应用没有办法一直正常运行，可以通过设置swap来缓解一下，虽然和内存的速度无法媲美，但是能一定程度缓解一下问题。

一、查看当前分区

查看当前系统的swap大小

<code>free -m

二、关闭现有的swap分区

将/etc/fstab文件中所有设置为swap的设备关闭，然后才能创建swap

sudo swapoff -a

三、创建新的swap文件

bs×count=最后生成的swap大小，这里设置8G

sudo dd if=/dev/zero of=/swapfile bs=1G count=8

四、设置权限

出于安全原因，交换文件应该只能被root用户读写

sudo chmod 600 /swapfile

 五、设置swap

sudo mkswap /swapfile

 六、启用swap

sudo swapon /swapfile

七、设置swap永久有效

编辑 sudo vim /etc/fstab 将下面内容添加到最后一行

/swapfile swap swap sw 0 0

全程操作记录

root@ubuntu:/# free -h

total used free shared buff/cache available

Mem: 23Gi 22Gi 203Mi 1.0Mi 777Mi 580Mi

Swap: 0B 0B 0B

root@ubuntu:/#

root@ubuntu:/# sudo dd if=/dev/zero of=/swapfile bs=1G count=8

8+0 records in

8+0 records out

8589934592 bytes (8.6 GB, 8.0 GiB) copied, 8.14848 s, 1.1 GB/s

root@ubuntu:/# sudo chmod 600 /swapfile

root@ubuntu:/# sudo mkswap /swapfile

Setting up swapspace version 1, size = 8 GiB (8589930496 bytes)

no label, UUID=7bab5b72-8602-4094-9211-622de895302d

root@ubuntu:/# sudo swapon /swapfile

root@ubuntu:/# sudo vim /etc/fstab

root@ubuntu:/#

root@ubuntu:/# cat /etc/fstab

# /etc/fstab: static file system information.

#

# Use 'blkid' to print the universally unique identifier for a

# device; this may be used with UUID= as a more robust way to name devices

# that works even if disks are added and removed. See fstab(5).

#

# <file system> <mount point> <type> <options> <dump> <pass>

# / was on /dev/ubuntu-vg/ubuntu-lv during curtin installation

/dev/disk/by-id/dm-uuid-LVM-L8iEhDkz0j7XOkZNxq1vqTybkF7AD0mbDMftF69chzey1qdN3t7jrCDJ1egzu2BE / ext4 defaults 0 1

# /boot was on /dev/sda2 during curtin installation

/dev/disk/by-uuid/ff68fd53-d03e-4dbe-91e1-414c0776da12 /boot ext4 defaults 0 1

/dev/mapper/ubuntu--vg2-database /database ext4 defaults 0 0

# swap

/swapfile swap swap sw 0 0

root@ubuntu:/#

root@ubuntu:/# free -h

total used free shared buff/cache available

Mem: 23Gi 4.5Gi 7.2Gi 1.0Mi 11Gi 18Gi

Swap: 8.0Gi 0B 8.0Gi

root@ubuntu:/#