[Lab 16.1] Swap files and openSUSE

albertgoma

Due to the fact that openSUSE's default filesystem is BTRFS, it doesn't allow creating swap files in the conventional way. The following must be done instead (As seen on the ArchWiki):

opensuse:~ # btrfs subvolume create /swap
Create subvolume '//swap'
opensuse:~ # btrfs filesystem mkswapfile --size 1g --uuid clear /swap/swapfile
create swapfile /swap/swapfile size 1.00GiB (1073741824)
opensuse:~ # swapon /swap
/swap

And then we can see the results:

opensuse:~ # cat /proc/swaps 
Filename                Type        Size        Used        Priority
...
/swap/swapfile                          file        1048572     0       -3
...

I assume the creation of a dedicated subvolume for the swap file must be to prevent it from being accidentally snapshotted alongside with other parts of the filesystem (i.e. by tools such as zypper and YaST when used with Snapper, such as in the default install).

albertgoma

To remove and delete the swap file:

opensuse:~ # swapoff /swap/swapfile
opensuse:~ # btrfs subvolume delete /swap
Delete subvolume 285 (no-commit): '//swap'

luisviveropena

Hi @albertgoma,

Thanks for the information!

Due to the fact that openSUSE's default filesystem is BTRFS, it doesn't allow creating swap files in the >conventional way.

I checked on the openSUSE documentation, and that's right for the root partition. You always can create another partition for specific purposes, including swap, with another filesystem.

I let this here for reference:

https://doc.opensuse.org/documentation/leap/archive/42.3/reference/html/book.opensuse.reference/cha.advdisk.html

Regards,
Luis.