First create an 1Gigabyte file.
opensuse:~# dd if=/dev/zero of=/swap bs=1024 count=1000000
1000000+0 records in
1000000+0 records out
1024000000 bytes (1.0 GB) copied, 28.7256 s, 35.6 MB/s
DD command to create the 1G file basically writing “0” into the file swap_1 in the “/” file system.
Create SWAP area
opensuse:~ # mkswap /swap
Setting up swapspace version 1, size = 999996 KiB
no label, UUID=4aada58e-d6f7-4053-adf1-8d4c79122d36
That sets up the file as a swap area.
Now, we’ll simply enable the swapfile, so that the system can start paging physical memory pages onto it.
opensuse:~ # swapon /swap
The system should now have an additional 1Gigabyte of swap area. Check it.
opensuse:~ # free -tom
total used free shared buffers cached
Mem: 998 973 24 0 20 795
Swap: 1716 0 1716
Total: 2714 973 1741
We now have 1.7Gigabytes of swap area.
To confirm the swap areas we have
opensuse:~ # swapon -s
Filename Type Size Used Priority
/dev/mapper/system-swap partition 757752 0 -1
/swap file 999992 0 -2
To make it permanent, we need to add an entry to the /etc/fstab file.:
/swap swap swap defaults 0 0
Where /swap is our new swap file and it instructs the system to mount it at system startup as a swap area.