Ubuntu/swap
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About
Newer versions of Ubuntu use a regular(ish) file for swap, rather than a partition -- so resizing it is now possible without rebooting or mucking around with fdisk.
Commands:
- swapon --show
- Confirms the swap-file status (default is currently 2 gigabytes)
- sudo fallocate -l 4G /swap4G
- creates a new swapfile-compatible 4 gigabyte file named
/swap4G - Regardless of what's implied by the tldp.org instructions, you can do this before disabling the old swapfile as long as you give it a different name.
- creates a new swapfile-compatible 4 gigabyte file named
- sudo chmod 0600 /swap4G
- Not required, but reduces warning messages and possible security holes.
- sudo mkswap /swap4G
- Mark the new file as a swapfile.
- sudo swapon /swap4G
- Tell the swap system to use the new file.
- sudo swapoff /swapfile
- Turn off usage of the given swapfile (
/swapfileis the name of the default) -- but make sure you've got enough RAM free first, or have set up another swapfile! - This will take some time, depending on how full this swapfile is.
- Yes, you can have two swapfiles in use simultaneously.
- Turn off usage of the given swapfile (
Then edit /etc/fstab to change the name of the swapfile you want to use. You can delete the old swapfile either before or after that, but safest to do it after.
Notes
- Linux Partition HOWTO: 9. Setting Up Swap Space
- 2020-02-11 How to Increase Swap Size on Ubuntu (using the new swapfile instead of partitioning)
- Note that you have to edit fstab for the change to persist after reboot.
- Also, it's not necessary to do swapoff except to stop using a given swapfile. You can add a new swapfile at any point, and the system will use more than one swapfile concurrently.
- 2020-02-11 How to Increase Swap Size on Ubuntu (using the new swapfile instead of partitioning)
- upgrade command for 16.04 LTS:
do-release-upgrade