Linux learning 24- Tencent cloud server is turned swap partition

Foreword

Recently, a small partner to buy Tencent cloud of a nuclear 1G entry-level server, find the deployment of multi-service post, will be automatically stopped container some of the docker's.
Buy a new host does not provide Tencent cloud Swap partition, reason is often because the host memory usage is too high, frequent use Swap, resulting in disk IO is too high, but declined overall server performance.
Adding Swap However, users can still use the way Swap files partition.

Start swap partition

First with the free -mview of the current situation partition, swap partition is displayed as 0

free -m

[root@VM_0_2_centos ~]# free -m
              total        used        free      shared  buff/cache   available
Mem:           3789         858        1579           0        1351        2638
Swap:             0           0           0

Create a new directory for the swap file, such as my directory / root / swap, create a file of a 2G

dd if=/dev/zero of=/root/swap bs=2048 count=1048576

[root@VM_0_2_centos ~]# dd if=/dev/zero of=/root/swap bs=2048 count=1048576
1048576+0 records in
1048576+0 records out
2147483648 bytes (2.1 GB) copied, 15.3681 s, 140 MB/s

This file is set to swap file

mkswap /root/swap

[root@VM_0_2_centos ~]# mkswap /root/swap
Setting up swapspace version 1, size = 2097148 KiB
no label, UUID=0d63d460-a558-4a60-9a7e-94e78be2dfc5

Modify the file permissions to 600

chmod 600 /root/swap

Enable swap file

swapon /root/swap

Boot from the start

Set boot from the start, you need to modify to modify the file / etc / fstab, add a line at the end /root/swap swap swap defaults 0 0

[root@VM_0_2_centos ~]# vi /etc/fstab
[root@VM_0_2_centos ~]# cat /etc/fstab 
UUID=4b499d76-769a-40a0-93dc-4a31a59add28            /                    ext4       noatime,acl,user_xattr 1 1
proc                 /proc                proc       defaults              0 0
sysfs                /sys                 sysfs      noauto                0 0
debugfs              /sys/kernel/debug    debugfs    noauto                0 0
devpts               /dev/pts             devpts     mode=0620,gid=5       0 0
/swap                 swap                swap       defaults              0 0
/root/swap            swap                swap       defaults              0 0
[root@VM_0_2_centos ~]# 

Delete the swap partition

Delete the swap partition

swapoff /root/swap
rm -f /root/swap