Comment 72 for bug 1768230

my /etc/initramfs-tools/conf.d/resume file contains one line

RESUME=UUID=99a2d3b2-0f29-4080-977c-35a5744279a8

I have tried several suggestions in this thread but I haven't found anything that works. I tried

RESUME=/dev/vg_system/lv_swap

then I ran the update-initramfs -u, as suggested. I got this:

update-initramfs: Generating /boot/initrd.img-4.15.0-43-generic
W: initramfs-tools configuration sets RESUME=/dev/vg_system/lv_swap
W: but no matching swap device is available.
I: The initramfs will attempt to resume from /dev/dm-1
I: (UUID=99a2d3b2-0f29-4080-977c-35a5744279a8)
I: Set the RESUME variable to override this.

I'm not what to do from here.