So this is what's happening after an unclean shutdown of the VM :
2018-10-11 21:26:57.837 UTC 5bbfc021.69e9 0 LOG: database system was interrupted; last known up at 2018-10-11 19:52:53 UTC
[...]
2018-10-11 21:26:57.919 UTC 5bbfc021.6a19 0 VCDB vc FATAL: the database system is starting up
2018-10-11 21:26:57.919 UTC 5bbfc021.69e9 0 PANIC: could not read file "pg_replslot/vpg_archiver/state", read 0 of 16: No such file or directory
2018-10-11 21:26:57.931 UTC 5bbfc021.6a1b 0 VCDB vc FATAL: the database system is starting up
[...]
2018-10-11 21:26:58.539 UTC 5bbfc021.69e7 0 LOG: startup process (PID 27113) was terminated by signal 6: Aborted
2018-10-11 21:26:58.539 UTC 5bbfc021.69e7 0 LOG: aborting startup due to startup process failure
2018-10-11 21:26:58.568 UTC 5bbfc021.69e7 0 LOG: database system is shut down
Anyone knows how to fix the database?