I don't think this is possible; you'd have multiple node instances trying to read/write a single data directory. This is not the intended operation, you'd likely end up with corrupt data.
If you must run multiple independent nodes and are worried about storage requirements, I'd recommend looking into 'pruning mode', it will limit the storage requirements for each node instance.
Note that you can copy the data directory folder of a synced node, so that you will not need to run through the initial block download and sync for each individual node (lots of savings in time and computation here). Just be sure to stop bitcoind before copying the data directory, and then start it up again once the copy is complete. This will help avoid potential data corruption/loss.
Thanks for the explanation. I agree, a node should be independent. A shared disk would be a single point of failure for such a cluster. With my question I had in mind that there's a lot of redundancy at the price of hard disks, but redundancy IS actually good for the network. – Michael – 2019-09-29T08:52:49.623