先自己增加一块磁盘

dd if=/dev/zero of=/tmp/newdisk bs=1M count =100

dd 操作磁盘从zero（盗零器）中产生0 到of 里面去 ，产生块大小1M 数量100 。

[root@Carlton ~]# mkswap -f /tmp/newdisk     格式化Setting up swapspace version 1, size = 102396 KiBno label, UUID=8fb9f68e-77da-4b86-b80e-7663edeb3c30[root@Carlton ~]# free -m             total       used       free     shared    buffers     cachedMem:           996        919         76         11         35        336-/+ buffers/cache:        547        449Swap:            0          0          0[root@Carlton ~]# swapon /tmp/newdisk [root@Carlton ~]# free -m             total       used       free     shared    buffers     cachedMem:           996        919         76         11         35        336-/+ buffers/cache:        547        448Swap:           99          0         99[root@Carlton ~]# swapoff /tmp/newdisk [root@Carlton ~]# free -m             total       used       free     shared    buffers     cachedMem:           996        919         76         11         35        336-/+ buffers/cache:        547        449Swap:            0          0          0