Sudo updatedb `/var/lib/mlocate/mlocate.db' is locked due to faulty drive, how to resolve permanently?

This 4.20.3 Arch system its BTRFS formatted / disk is without free space left. It turns out that mlocate is the cause: # du -h --exclude=Volumes -- * 2>/dev/null | sort -hr | head -2 11G var 9.6G var/lib/mlocate The question https://unix.stackexchange.com/questions/82985/updatedb-can-not-open-a-temporary-file-for-var-lib-mlocate-mlocate-db accepted answer suggests to prepend sudo, though that doesn't change a thing: # sudo updatedb updatedb: `/var/lib/mlocate/mlocate.db' is locked (probably by an earlier updatedb) There seems to be a temporary file in /var/lib/mlocate that is eating up all disk space: # ls -lh var/lib/mlocate/ -rw-r----- 1 root locate 1.1M Oct 21 00:00 mlocate.db -rw------- 1 root root 9.6G Dec 30 19:46 mlocate.db.PRvfsw Could the root cause be the .timer update job that is hanging? # systemctl status updatedb.timer * updatedb.timer - Daily locate database update Loaded: loaded (/usr/lib/systemd/system/updatedb.timer; static; vendor preset: disabled) Active: active (running) since Mon 2019-10-21 16:05:10 CEST; 2 months 9 days ago Trigger: n/a Both restart and stop don't remove the temporary large .db file and updatedb still returns locked. There seems to be an updatedb process still running: # ps -ef | grep updatedb root 3249 1 99 Oct22 ? 213573-14:47:11 /usr/bin/updatedb I know I can kill this process. The root cause is most likely a faulty USB stick: # ls /Volumes/RM_GUE__ ls: cannot access '/Volumes/RM_GUE__/'$'\001\020': Input/output error ls: cannot access '/Volumes/RM_GUE__/)': Input/output error Though the next time a USB stick becomes faulty, / will fill up again. ###updatedb.conf The updatedb.conf options don't bring me any useful filter option: - by path: I can't guess the name that the partition will have after corruption - by filesystem: In this case VFAT was corrupted (and read-only), though I can't look in to the future which file system will get corrupted. How to resolve this issue neat and permanently, for example by limiting the duration that updatedb.timer may run and/or skipping disks which suffer input/output errors, or limit the file size LimitFSIZE= or even something better?