Hello, We were working on expanding one of our clusters (Ussuri on Ubuntu 18.04) and are wondering about the rebalance behavior of swift-ring-builder. When we run it in debug mode on a 15/4 EC ring, we see this message about "Unable to finish rebalance plan after 2 attempts" and are seeing 100% partitions reassigned. DEBUG: Placed 10899/2 onto dev r1z3-10.40.48.72/d10 DEBUG: Placed 2183/3 onto dev r1z5-10.40.48.76/d11 DEBUG: Placed 1607/1 onto dev r1z3-10.40.48.70/d28 DEBUG: Assigned 32768 parts DEBUG: Gather start is 10278 (Last start was 25464) DEBUG: Unable to finish rebalance plan after 2 attempts Reassigned 32768 (100.00%) partitions. Balance is now 63.21. Dispersion is now 0.00 ------------------------------------------------------------------------------- NOTE: Balance of 63.21 indicates you should push this ring, wait at least 1 hours, and rebalance/repush. ------------------------------------------------------------------------------- Moving 100% seems scary, what does that mean in this situation? Is this message because 1 fragment from every partition is moved and that is the most that it can do per rebalance because they are technically the same partition? When we compare the swift-ring-builder output (partitions per device) between rebalances we can see some partitions move each time until we no longer see the push/wait/rebalance message again. So it's not really moving 100% partitions. Reid