Swap-file

Is it possible to have a swap-file in Linux
and not a full swap-partition.
LarsCAsked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

x
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

dspencerCommented:
Not that I know of.  (I would just say "no, it is not", except for the possibility that since it's the Linux community and all, *anything* is remotely possible. =])

The utilities dealing with swap interaction, specifically mkswap and swapon/off, and the way it is accessed to the system through /etc/fstab, seem to be irrevocably tied to swap space being on one or more separate partitions.

See the Installation-HOWTO and (if you're interested in possibly sharing swapfile space with a Windows 3.x installation) the Swap-Space mini-HOWTO for supporting details.

Sorry!

(And just as long as we're on the subject of separate partitions:  my favorite schema is /, /usr, /usr/local, /home, /var, /tmp, and swap, with sharing as appropriate for your installation. Post another question if you want better explanation :) )
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
stgreenwaltCommented:
The accepted solution is wrong.  You can create a swap file in Linux that is not a part of a separate partition as follows.  This creates a 1GB swap file:

All from a root prompt (or preceed each line with sudo):
     $ sudo dd if=/dev/zero of=/mnt/swapfile bs=1024 count=1048576
     $ sudo chmod 600 /mnt/swapfile
     $ sudo mkswap /mnt/swapfile
     $ sudo swapon /mnt/swapfile
     $ sudo echo '/mnt/swapfile none swap sw 0 0' >> /etc/fstab
     $ sudo sysctl vm.swappiness=10

Open in new window

Check if your new swap is working;
    $ sudo swapon -s

Open in new window

   If '/mnt/swapfile' appears in the results, then it is working.

Other notes:

If swappiness=0, swapping will occur only if RAM is exhausted.  Increasing the number increases the likelihood that swap will be used even when RAM not exhausted.  You have to experiment with this.  A value of 60 would be reasonable, but a lot depends on your system configuration.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Linux

From novice to tech pro — start learning today.