mjhjmtu

Here is my lsblk -a list:

NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 10G 0 disk
├─sda1 8:1 0 1G 0 part /boot
└─sda2 8:2 0 9G 0 part
 ├─cl-root 253:0 0 8G 0 lvm /
 └─cl-swap 253:1 0 1G 0 lvm [SWAP]
sdb 8:32 0 16G 0 disk
sr0 11:0 1 1024M 0 rom
drbd0 147:0 0 2G 0 disk

I want to remove drbd0. How to do?

rm'ing nodes in /dev/ will not do what I suggested and remove the DRBD device. E.g. you should see that the kernel view of block devices in /sys/class/block is not affected by such changes.

Removing the device node will hide it from lsblk, but it would not cause any claimed resources to be released! This seems like a bad idea.

Rebooting should remove any weird DRBD devices that you're not using any more. (E.g. removed from drbd config, but still exist for some unknown reason).

"module load/unload" would be a way to avoid a reboot, if that's what you wanted. modprobe -r drbd to unload. It would require that you have no other DRBD devices in use.

If you believed the drbd daemon was messing around with creating or renaming devices in /dev at the same time as udev / devtmpfs is running, and genuinely had a bug which left behind a stale device node (and some stale cache in lsblk), then you'd better do a full reboot to clear up the mess. Because that would be some really broken software, nothing should be doing that anymore.

As you have stopped drdb you may want to check the thread and follow the recommendation and just remove the device file in /dev. Here is extract from the mentioned page:

and we also have the drbd device in /dev/ directory, we want to delete
de drbd1 from /dev.

brw-rw---- 1 root disk 147, 0 2009-03-18 15:34 /dev/drbd0

brw-rw---- 1 root disk 147, 1 2009-03-18 15:34 /dev/drbd1

brw-rw---- 1 root disk 147, 2 2009-03-18 15:34 /dev/drbd2

brw-rw---- 1 root disk 147, 3 2009-03-18 15:41 /dev/drbd3

brw-rw---- 1 root disk 147, 4 2009-03-18 15:41 /dev/drbd4

you can of course delete the device nodes, if it makes you happy. only
it won't magically re-appear in case you want to use it again, (unless
you do a reboot or module unload/load). so you would need to mknod it
again, if you need it again.

lsblk has a -e option to exclude devices by major device numbers.

The drbd devices in your lsblk output above have a major number of 147, so this will exclude them from the list:

lsblk -a -e 147

This will not remove any drbd device nodes from your system or interact in any way with the DRBD service, it will just exclude the drbd devices from lsblk's output.