How to disable swap in App VM (Qubes OS R4.2.3)

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1

Hi,

I have setup ZRAM for my App VMs. It worked. I also tried to disable swap so I can use the swap partition as a backing device for ZRAM so it can use it for pages that it cannot compress. However I noticed that even after I commented out the fstab entry for swap in debian-12 template, the swap partition was still mounted as swap. Apparently some scripts in initram and systemd activates swap. Is it possible to disable that?

I can disable swap in zram activation script, but it will be nice not to activate it in the first place.

Any suggestions?

2

You shouldn’t disable swap at boot time, as stated in the comment in /usr/share/initramfs-tools/scripts/local-top/qubes_cow_setup:

    # enable swap right now, because systemd may want to run fsck in initramfs
    # already and it require some more memory

So it’s better to disable swap in /dev/xvdc1 and setup ZRAM after the qubes boot e.g. in /rw/config/rc.local.

Also you can only use /dev/xvdc1 for ZRAM, not the whole /dev/xvdc, because /dev/xvdc is also used for volatile changes in root partition: