elasticsearch/docs/reference/modules/indices/recovery.asciidoc

[[recovery]]
=== Indices Recovery

Peer recovery syncs data from a primary shard to a new or
existing shard copy.

Peer recovery automatically occurs when {es}:

* Recreates a shard lost during node failure
* Relocates a shard to another node due to a cluster rebalance or changes to the
<<modules-cluster, shard allocation settings>>

You can view a list of in-progress and completed recoveries using the
<<cat-recovery, cat recovery API>>.

[float]
==== Peer recovery settings

`indices.recovery.max_bytes_per_sec` (<<cluster-update-settings,Dynamic>>)::
Limits total inbound and outbound recovery traffic for each node.
Defaults to `40mb`.
+
This limit applies to nodes only. If multiple nodes in a cluster perform
recoveries at the same time, the cluster's total recovery traffic may exceed
this limit.
+
If this limit is too high, ongoing recoveries may consume an excess
of bandwidth and other resources, which can destabilize the cluster.

[float]
==== Expert peer recovery settings
You can use the following _expert_ setting to manage resources for peer
recoveries.

`indices.recovery.max_concurrent_file_chunks` (<<cluster-update-settings,Dynamic>>, Expert)::
Number of file chunk requests sent in parallel for each recovery. Defaults to
`2`.
+
You can increase the value of this setting when the recovery of a single shard
is not reaching the traffic limit set by `indices.recovery.max_bytes_per_sec`.