Ubuntu20.04调整swap分区大小笔记

Ubuntu20.04调整swap分区大小笔记

参考：https://blog.csdn.net/sunyuhua_keyboard/article/details/142485764

第一步 禁用swap

$ 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).
#
#                
# / was on /dev/sda2 during installation
UUID=bbc5a35b-b700-4792-a9ba-7d643a95f9c5 /               ext4    errors=remount-ro 0       1
# /boot/efi was on /dev/sda1 during installation
UUID=7CDB-0C3D  /boot/efi       vfat    umask=0077      0       1
/swapfile                                 none            swap    sw              0       0
UUID=9bfb904b-d2b4-43aa-ba49-916e6c4d6320 /root/workspace ext4    defaults        0       0

$ swapon --show
NAME      TYPE SIZE USED PRIO
/swapfile file   2G   1G   -2

$ free -h
              总计         已用        空闲      共享    缓冲/缓存    可用
内存：        15Gi       1.0Gi       7.2Gi        45Mi       7.3Gi        14Gi
交换：       2.0Gi       1.0Gi       983Mi

$ swapoff -a

$ swapon --show

$ free -h          
              总计         已用        空闲      共享    缓冲/缓存    可用
内存：        15Gi       2.0Gi       6.1Gi        73Mi       7.4Gi        13Gi
交换：          0B          0B          0B

第二步 切换swapfile文件

$ rm /swapfile

$ ls -al / | grep swapfile

$ fallocate -l 16G /swapfile

$ ls -al / | grep swapfile
-rw-r--r--   1 root root 17179869184 12月 10 14:13 swapfile

$ chmod 600 /swapfile

$ ls -al / | grep swapfile
-rw-------   1 root root 17179869184 12月 10 14:13 swapfile

$ mkswap /swapfile
正在设置交换空间版本 1，大小 = 16 GiB (17179865088  个字节)
无标签， UUID=8127980c-6104-424c-952b-d394bbce95e5

$ ls -al / | grep swapfile
-rw-------   1 root root 17179869184 12月 10 14:16 swapfile

第三步 启用新的swap

$ swapon /swapfile  

$ swapon --show   
NAME      TYPE SIZE USED PRIO
/swapfile file  16G   0B   -2

$ free -h                 
              总计         已用        空闲      共享    缓冲/缓存    可用
内存：        15Gi       2.0Gi       6.8Gi        73Mi       6.6Gi        13Gi
交换：        15Gi          0B        15Gi

$ 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).
#
#                
# / was on /dev/sda2 during installation
UUID=bbc5a35b-b700-4792-a9ba-7d643a95f9c5 /               ext4    errors=remount-ro 0       1
# /boot/efi was on /dev/sda1 during installation
UUID=7CDB-0C3D  /boot/efi       vfat    umask=0077      0       1
/swapfile                                 none            swap    sw              0       0
UUID=9bfb904b-d2b4-43aa-ba49-916e6c4d6320 /root/workspace ext4    defaults        0       0