@renchap @Claire I think good use of bloom filters would be when you want to batch those deletes. Now instead of sending a single SHA to delete, you put all the SHAs in an appropriately sized bloom filter and send that. 1000 deletes with a 1-in-a-trillion false positive rate is a 7KB filter. Instance2 receiving such a bloom filter delete from Instance1 would SHA all its local Instance1 actor ids and check them against the filter. If it gets a match it does the delete.