Number of items in a bucket

[Couchbase Ent. server 4.5]

  • I have a cluster with 4 identical servers, running Ubuntu.
  • I have a bucket with X documents, lets say 1 million.
  • In the management GUI, i see the correct count of documents in the Buckets page.

If I stop the service (or reboot) on one of the server (say “service couchbase-server stop”) - the total number of “items” in the GUI drops. By 25%. Once the server/service is back up - the number of items climbs back to its original number.

Now, the bucket is set with “Replicas” = “On” and “Number of replica (backup) copies” = “2”. Which, to my understanding, means there will be 2 additional copies of each document? so 3 in total?
So how come the number of available documents drops when a server goes missing for a while?
(even if it’s 2 in total, it’s still doesn’t explain this).



This means we don’t understand something fundamental about the “redundancy” factor here, or something is broken in our setup?