I just checked the status and nothing has changed. There is one replica shard with 0 documents still initializing. This is the output of GET _recovery shortly after I set concurrent allocations to 1 and this one I captured a few minutes ago. Replica shard with Id 1 of index wiki_wikicontract_1421_shared_e9529131-b634-4873-b279-c9dd8a0bd2e5 is initializing on node es-d08-rm. The corresponding primary shard is allocated on es-d01-rm. Let me know if you need more information.