[root@sannian mnt]# dd if=/dev/zero of=/mnt/swapfile bs=1M count=2048020480+0 records in20480+0 records out21474836480 bytes (21 GB) copied, 193.865 s, 111 MB/s

开机自挂载：

[root@sannian swap]# mkswap   swapfile[root@sannian swap]# vim /etc/fstab /mnt/swap/swapfile   swap              swap        defaults        0 0

挂载

[root@sannian swap]# swapon  /mnt/swap/swapfile swapon: /mnt/swap/swapfile: insecure permissions 0644, 0600 suggested.

去除：

[root@sannian swap]# swapoff /mnt/swap/swapadd

查看是不事挂上去了？

[root@sannian swap]# free -m              total        used        free      shared  buff/cache   availableMem:           1839         196         999           0         642        1471Swap:         20479           0       20479