CHAPTER 5 File System Management
/dev/sd1b swap swap rw 0 0
You can make a file suitable for use as swap with the mkfile command found in /usr/etc (SunOS 4.1.X) or /usr/sbin (SunOS 5.X), e.g.:
# mkfile 20m /export/swap/swapfile
Under SunOS 4.1.X you add this to the swap area with the swapon command, i.e.:
# /usr/etc/swapon /export/swap/swapfile
To automatically add this swap space when booting add the above entry to /etc/rc.local
For SunOS 5.X you would use the swap command with the -a (add) option to add the swapfile, i.e.:
# /usr/sbin/swap -a /export/swap/swapfile
You can make an entry in /etc/vfstab to have this automatically added to the swap space after a reboot.
/usr/swapfile - - swap - no -
To display the available swap space under SunOS 5.X do the following:
# swap -l
swapfile dev swaplo blocks free
swapfs - 0 123776 118600
/dev/dsk/c0t3d0s1 32,25 8 66232 50184
/usr/swapfile - 8 30712 14360
To display the total swap space use swap -s in SunOS 5.X or pstat -s in SunOS 4.X, e.g.:
# swap -s
total: 18780k bytes allocated + 6444k reserved = 25224 used, 30084 available
SunOS 5.X allows you to delete swap space at any time. To do this use:
# swap -d /export/swap/swapfile
When the swap file is no longer in use it will be deleted from the available swap space and will no longer be accessible for swapping.
Swapping to a partition is a little more efficient than swapping to a file, though with the latest OS versions the difference is small. Swap files are convenient to set up, especially if you are only going to use them for a short time period. You can then delete them when the need has expired.