root@miyazaki portage-2.1.10.56 # dd if=/dev/zero of=/swap bs=1M count=1024
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 12.2196 s, 87.9 MB/s
root@miyazaki portage-2.1.10.56 # chmod 600 /swap
root@miyazaki portage-2.1.10.56 # mkswap /swap
mkswap: /swap: warning: don't erase bootbits sectors
        on whole disk. Use -f to force.
Setting up swapspace version 1, size = 1048572 KiB
no label, UUID=8f3199e6-42dd-46c9-be7f-0c6b87cf17a4
root@miyazaki portage-2.1.10.56 # swapon /swap
swapon: /swap: swapon failed: Operation not permitted
root@miyazaki portage-2.1.10.56 # ls -l /swap
-rw------- 1 root root 1073741824 Apr  8 10:45 /swap