创建swap内存空间

创建swap内存空间

云上购买的cvm机器一般都没有开启swap空间, 稍微npm build编译就会导致内存不够, 整个机器 oom 丢失响应, 开始强制删任务, 虽然并不会重启.

参考文档

Linux内存拓展（内存不足SWAP解决方案）

https://www.cnblogs.com/Axianba/p/13131620.html

执行实录

• 创建swap文件

ubuntu@VM-0-4-ubuntu:~$ sudo dd if=/dev/zero of=/swapfile bs=1024 count=4096000
4096000+0 records in
4096000+0 records out
4194304000 bytes (4.2 GB, 3.9 GiB) copied, 14.3766 s, 292 MB/s

ubuntu@VM-0-4-ubuntu:~$ ls -alh /
total 4.0G
drwxr-xr-x  22 root root 4.0K Oct 13  2022 lib
-rw-r--r--   1 root root 4.0G Jun 13 23:31 swapfile
dr-xr-xr-x  13 root root    0 May 30 19:24 sys
drwxrwxrwt  14 root root 4.0K Jun 13 23:30 tmp
drwxr-xr-x  13 root root 4.0K May 30 21:10 usr

• 加载swap

ubuntu@VM-0-4-ubuntu:~$ sudo mkswap /swapfile
mkswap: /swapfile: insecure permissions 0644, 0600 suggested.
Setting up swapspace version 1, size = 3.9 GiB (4194299904 bytes)
no label, UUID=2e16c959-2695-4e71-a069-a45969f2e9a4

ubuntu@VM-0-4-ubuntu:~$ sudo swapon /swapfile
swapon: /swapfile: insecure permissions 0644, 0600 suggested.

ubuntu@VM-0-4-ubuntu:~$ swapon -s
Filename                                Type            Size    Used    Priority
/swapfile                               file            4095996 0       -2
ubuntu@VM-0-4-ubuntu:~$ htop

```bash
free -h
              total        used        free      shared  buff/cache   available
Mem:           3.4G        1.7G        252M         19M        1.5G        1.5G
Swap:          3.9G        577M        3.3G

• 持久化开机启动

ubuntu@VM-0-4-ubuntu:~$ sudo vim /etc/fstab

ubuntu@VM-0-4-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>
UUID=5ba34c3d-bd14-451d-a7d8-09a64009e3f1       /               ext4    errors=remount-ro 0       1
/swapfile swap    swap    defaults      0    0

ubuntu@VM-0-4-ubuntu:~$ sudo mount -a

ubuntu@VM-0-4-ubuntu:~$ sudo mount -fav
/                        : ignored
swap                     : ignored
ubuntu@VM-0-4-ubuntu:~$ sudo findmnt --verify --verbose
/
   [ ] target exists
   [ ] FS options: errors=remount-ro
   [ ] UUID=5ba34c3d-bd14-451d-a7d8-09a64009e3f1 translated to /dev/vda1
   [ ] source /dev/vda1 exists
   [ ] FS type is ext4
swap
   [W] non-bind mount source /swapfile is a directory or regular file
   [ ] FS type is swap

0 parse errors, 0 errors, 1 warning

chatgpt 解释

dd 命令

mkswap和swapon命令

mount命令