Ubuntu doesn't recognize my swap partition

**Buntumatic** · January 10th, 2012

First run mkswap on it. Like this

Code:

mkswap /dev/sdX

Then let your Linux know you want to use it with swapon. Like this

Code:

swapon /dev/sdX

That's it, repeat it for every swap partition you have.
Of course, if you want them activated automatically next reboot add respective lines to your fstab.
You can also turn them off with swapoff. Like this

Code:

swapoff /dev/sdX

Note, activating and deactivating swap does not require reboot, as with everything else in Linux (except kernel upgrade).

**Buntumatic** · January 10th, 2012

Just to illustrate the fun working with Linux.

Once upon time I was building Openoffice on Gentoo, the box had not much resources, I think it had 1 GiB of RAM and 512 MiB of swap. I had conky running on the desktop and I saw memory filled up and swap filling up, too. Compiling Openoffice is time consuming, I did not want it to be killed by OOM killer.
I quickly did

Code:

dd if=/dev/zero of=/swapfile bs=1024 count=1M

this created 1 gigabyte file, then I made it swap space

Code:

mkswap /swapfile

and finally I activated it

Code:

swapon /swapfile

and voila! My compilation process was saved.

**bobman321123** · January 11th, 2012

So if I were to want to add another partition to swap permanently, all I would do is to add another line that says the bellow to the fstab?

Code:

"name of partition" swap

**Buntumatic** · January 11th, 2012

Look at existing line for swap in /etc/fstab. There are a few fields to be filled.

1. device
2. mount point
3. type
4. mount options

See man fstab for more.