Creating the Swap File

# dd if=/dev/zero of=/swapfile bs=1024 count=512000

512000+0 records in

512000+0 records out

524288000 bytes (524 MB) copied, 10.411 s, 50.4 MB/s

# mkswap /swapfile

Setting up swapspace version 1, size = 511996 KiB

no label, UUID=7baa7ca8-c840-4c6e-bd53-038ce4e9a477

Enabling the Swap File

# swapon /swapfile

View Swap File

# free

                total       used       free     shared    buffers     cached

Mem:        501840     496152       5688          0       8964     253104

-/+ buffers/cache:     234084     267756

Swap:       511996          0     511996

Starting every time

Edit /etc/fstab, add a line after all：

/swapfile       none    swap    defaults      0       0