How to increase relocation concurency?

Elastic Stack Elasticsearch
1

I'm looking at _cat/recovery stats.

I have 7 shards marked as relocating, but it seems that only 1 shard at a time is relocated.

Every time I run _cat/recovery 6 shards are at 0.1% while 1 slowly grows until completed and then another one starts.

2

Take a look at https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-indices.html#recovery