Nov 07 2008
Additional Swap in File on Linux/Solaris
You need more swap but there’s no more disk space left to create a partition? Here’s a quick and easy fix creating a swap file on the existing filesystem. No reboot needed!
Solaris
[root@solaris]$ mkfile 1024m /export/tmpswap
[root@solaris]$ swap -a /export/tmpswap
[root@solaris]$ swap -l
swapfile dev swaplo blocks free
/dev/dsk/c1t0d0s1 55,65 8 4160824 4160824
/export/tmpswap - 8 2097144 ©
Linux
[root@linux]$ dd if=/dev/zero of=tmpswap bs=1024 count=10240
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 0.528435 seconds, 19.8 MB/s
[root@linux]$ mkswap tmpswap
Setting up swapspace version 1, size = 10481 kB
[root@linux]$ swapon tmpswap
[root@linux]$ swapon -s
Filename Type Size Used Priority
/dev/hda2 partition 409648 0 -1
/tmp/tmpswap file 10232 0 -2
Do not use swap files on a personal computer that is configured to “suspend to disk” since it requires a dedicated partition to save the memory content while going to hibernation. This is not a problem on servers.