I couldn't find a recent answer for this (but my search skills after 16 hours of 5-to-6-upgrade-work are a little... downscaled). Long story short: I have to move 14 shards from a broken-beyond-repair node, which is booted in rescue mode, to a working node.
Can I simply
rsync -a --ignore-existing /var/lib/elasticsearch/nodes/0/indices from the broken node to the working node?
Do I need to stop the working node during the sync?
Thanks in advance!