[Linux] 手把手教您扩展虚拟内存

[root@chenfancentos ~]# free -m
       total     used     free   shared  buffers   cached
Mem:       988    164    823      0     26     48
-/+ buffers/cache:     90    898
Swap:     1999      0     1999

[root@chenfancentos ~]# dd if=/dev/zero of=/tmp/swapfile  bs=300M count=1
记录了1+0 的读入
记录了1+0 的写出
314572800字节(315 MB)已复制，13.9027 秒，22.6 MB/秒
[root@chenfancentos ~]# du  -h /tmp/swapfile
300M  /tmp/swapfile

[root@chenfancentos ~]# mkswap -f /tmp/swapfile
Setting up swapspace version 1, size = 307196 KiB
no label, UUID=c4e2a8b1-fa09-41ab-bcbf-63c273ed9598

[root@chenfancentos ~]# cat /etc/fstab
# /etc/fstab
# Created by anaconda on Sat Apr  2 19:37:01 2016
#
# 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=301b2f9f-91d3-47dd-8a43-d377cba1cd5c /             ext4  defaults    1 1
UUID=812455f9-a63f-4b09-9336-05e3ada6f9a7 /boot           ext4  defaults    1 2
UUID=416480d0-662c-406c-a328-b4c2f370577b swap          swap  defaults    0 0
tmpfs           /dev/shm        tmpfs   defaults    0 0
devpts          /dev/pts        devpts  gid=5,mode=620  0 0
sysfs           /sys          sysfs   defaults    0 0
proc          /proc           proc  defaults    0 0
/tmp/swapfile      swap           swap  defaults    0 0

[root@chenfancentos ~]# swapon /tmp/swapfile
[root@chenfancentos ~]# free -m
       total     used     free   shared  buffers   cached
Mem:       988    136    852      0     10     50
-/+ buffers/cache:     74    913
Swap:     2299      0     2299