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
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:/# 
