- Unix Commands Reference
- Unix - Tutorial Home
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
swapon - Unix, Linux Command
NAMEswapon, swapoff - enable/disable devices and files for paging and swapping
SYNOPSIS/sbin/swapon [-h -V]
/sbin/swapon -a [-v] [-e]
/sbin/swapon [-v] [-p priority] specialfile ...
/sbin/swapoff [-h -V]
/sbin/swapoff specialfile ...
DESCRIPTIONSwapon is used to specify devices on which paging and swapping are to take place.
The device or file used is given by the specialfile parameter. It may be of the form -L label or -U uuid to indicate a device by label or uuid.
Calls to swapon normally occur in the system multi-user initialization file /etc/rc making all swap devices available, so that the paging and swapping activity is interleaved across several devices and files.
Normally, the first form is used:
|-a||All devices marked as swap swap devices in /etc/fstab are made available, except for those with the noauto option. Devices that are already running as swap are silently skipped.|
|-e||When -a is used with swapon, -e makes swapon silently skip devices that do not exist.|
|Use the partition that has the specified label. (For this, access to /proc/partitions is needed.)|
|Specify priority for swapon. This option is only available if swapon was compiled under and is used under a 1.3.2 or later kernel. priority is a value between 0 and 32767. Higher numbers indicate higher priority. See swapon(2) for a full description of swap priorities. Add pri=value to the option field of /etc/fstab for use with swapon -a.|
|-s||Display swap usage summary by device. Equivalent to "cat /proc/swaps". Not available before Linux 2.1.25.|
|-U uuid||Use the partition that has the specified uuid. (For this, access to /proc/partitions is needed.)|
NOTEYou should not use swapon on a file with holes. Swap over NFS may not work.
/dev/sd?? standard (SCSI) paging devices
/etc/fstab ascii filesystem description table
HISTORYThe swapon command appeared in 4.0BSD.