centos 7 添加swap

　

添加一个8G 的swap

cd /
dd if=/dev/zero of=/swapfile bs=1k count=8192000
mkswap /swapfile
chmod 0600 /swapfile
swapon /swapfile 
echo "/swapfile swap swap defaults 0 0" >> /etc/fstab 

详情见下面

[root@lab01 /]# cd /
[root@lab01 /]# dd if=/dev/zero of=/swapfile bs=1k count=2048000
2048000+0 records in
2048000+0 records out
2097152000 bytes (2.1 GB) copied, 14.1909 s, 148 MB/s
[root@lab01 /]# free -m
              total        used        free      shared  buff/cache   available
Mem:           1838          70          67           0        1699        1599
Swap:             0           0           0
[root@lab01 /]# mkswap /swapfile 
Setting up swapspace version 1, size = 2047996 KiB
no label, UUID=0cc4aeeb-a55d-430e-8671-297f33bde299
[root@lab01 /]# chmod 0600 /swapfile 
[root@lab01 /]# swapon /swapfile 
[root@lab01 /]# free -m
              total        used        free      shared  buff/cache   available
Mem:           1838          72          81           0        1683        1597
Swap:          1999           0        1999
[root@lab01 /]# echo "/swapfile swap swap defaults 0 0" >> /etc/fstab 
[root@lab01 /]# cat /etc/fstab 

#
# /etc/fstab
# Created by anaconda on Thu Jul 11 02:52:01 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
UUID=1114fe9e-2309-4580-b183-d778e6d97397 /                       ext4    defaults        1 1
/swapfile swap swap defaults 0 0