Setting up a second swap partition for Linux [1]

In my last post I waxed lyrical about the merits of the Linux file system and how it is possible to have two swap partitions. Today I am setting up just that in my computer. It has an existing SSD with 100 GB available for swap, and due to an upgrade on the other computer, another 120 GB SSD has become available to install into it to add a second swap partition thereby more than doubling the swap space. This means the system should be able to edit very large Gimp files up to 50 GB whereas at the moment it can only handle ones up to about 20 GB because of all the other stuff I usually have running on it.

The first step to achieve this, having installed the disk and found it is in the system as /dev/sdc, is to make life easier and install GPartEd, the graphical partition editor (preferable to using command line in this instance). We can then use GPartEd to remove any existing partitions on the disk, and then allocate the entire space on it as a swap partition.

The next step is to run the mkswap command on our new partition (although it looks like GPartEd in fact already did this step)

And then we can use the swapon command to activate it:

after which running swapon -s will list the swaps currently in use which we find lists both of them and also conveniently the KDE system load monitor widget tells me the swap is now 198 GiB in size (it was 87 GiB and the new SSD added 111 GiB).

To permanently add the second swap partition it needs to be put into /etc/fstab:

UUID=83c0e622-bcdc-41fd-a1ce-ec3f6c88bfcc none            swap    sw              0       0which is basically copying the previous swap file entry except for the UUID which we get from running blkid

Then I tested by two Gimp projects at the same time that are around 40 GB in total. Originally the first one would not even load in the system, while the second one would use the entire swap space. Loading both together only used less than half of the new swap space, making it possible to work on them without any concerns about the system running out of swap and crashing Gimp.