Looks like a problem in entry forwarding.

Here is test scenario:

• DIST numOwners=2, start with 4 nodes cluster then normal shutdown 1 node during load
• HotRod putIfAbsent accesses from 40 threads (1 process, 1 remote cache instance), 40000 entries total

After the test run, the numberOfEntries on each node are:

• node1: 26608
• node2: 26622
• node3: 26746
• node4: 0

Total is 79976 and HotRod client received 11 errors, so 79976 + (11 * 2) = 79998. It means 1 entry is completely missing.

Let's take a look at the missing entry, hash(thread16key59) = 574ff563.

Current CH: owners(574ff563) are [node4, node1]

The events sequence is:

• hotrod -> node1
• node1 forwarding it to primary owner node4
• node4 doesn't process the forwarded entry, shutdown

Result owners(7c29bccb) is [] empty. This entry is completely lost without any errors.