Shard recovery thread count

Elastic Stack Elasticsearch
1

I have noticed in my cluster that there are maximum of 2 recovery tasks running whenever shard relocation happens.
Is this a configurable setting?
I would like to experiment with more threads moving shards to speed up the process.
Reason being the hard limit seems to prevent new index from assigning replica to a node.
When I removed some old indices, the cluster goes into a shard balancing mode.
This is fine. But we have hourly index being created and the replica is being set to unassigned for a prolong period of time, until one of the "recovery/relocation" task is done.
Is this normal?
We are running ES 7.4.1

Thanks.

2

Hi @linkerc, This may help you out.

Index Shard Allocation

Index shard stores API

Index recovery API

3

Thanks.
Unfortunately, they don't help.
Those are just providing info on recovery tasks.
I am looking for a way to increase the number of simultaneous recovery tasks.

4

I believe this is controlled through the cluster level shard allocation settings.

5

thank for the link.
I'll digest it further.