OpenSearch/docs/reference/cat/recovery.asciidoc

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[[cat-recovery]]
== cat recovery
The `recovery` command is a view of index shard recoveries, both on-going and previously
completed. It is a more compact view of the JSON <<indices-recovery,recovery>> API.
A recovery event occurs anytime an index shard moves to a different node in the cluster.
This can happen during a snapshot recovery, a change in replication level, node failure, or
on node startup. This last type is called a local gateway recovery and is the normal
way for shards to be loaded from disk when a node starts up.
As an example, here is what the recovery state of a cluster may look like when there
are no shards in transit from one node to another:
[source,shell]
----------------------------------------------------------------------------
> curl -XGET 'localhost:9200/_cat/recovery?v'
index shard time type stage source target files percent bytes percent
wiki 0 73 gateway done hostA hostA 36 100.0% 24982806 100.0%
wiki 1 245 gateway done hostA hostA 33 100.0% 24501912 100.0%
wiki 2 230 gateway done hostA hostA 36 100.0% 30267222 100.0%
---------------------------------------------------------------------------
In the above case, the source and target nodes are the same because the recovery
type was gateway, i.e. they were read from local storage on node start.
Now let's see what a live recovery looks like. By increasing the replica count
of our index and bringing another node online to host the replicas, we can see
what a live shard recovery looks like.
[source,shell]
----------------------------------------------------------------------------
> curl -XPUT 'localhost:9200/wiki/_settings' -d'{"number_of_replicas":1}'
{"acknowledged":true}
> curl -XGET 'localhost:9200/_cat/recovery?v'
index shard time type stage source target files percent bytes percent
wiki 0 1252 gateway done hostA hostA 4 100.0% 23638870 100.0%
wiki 0 1672 replica index hostA hostB 4 75.0% 23638870 48.8%
wiki 1 1698 replica index hostA hostB 4 75.0% 23348540 49.4%
wiki 1 4812 gateway done hostA hostA 33 100.0% 24501912 100.0%
wiki 2 1689 replica index hostA hostB 4 75.0% 28681851 40.2%
wiki 2 5317 gateway done hostA hostA 36 100.0% 30267222 100.0%
----------------------------------------------------------------------------
We can see in the above listing that our 3 initial shards are in various stages
of being replicated from one node to another. Notice that the recovery type is
shown as `replica`. The files and bytes copied are real-time measurements.
Finally, let's see what a snapshot recovery looks like. Assuming I have previously
made a backup of my index, I can restore it using the <<modules-snapshots,snapshot and restore>>
API.
[source,shell]
--------------------------------------------------------------------------------
> curl -XPOST 'localhost:9200/_snapshot/imdb/snapshot_2/_restore'
{"acknowledged":true}
> curl -XGET 'localhost:9200/_cat/recovery?v'
index shard time type stage repository snapshot files percent bytes percent
imdb 0 1978 snapshot done imdb snap_1 79 8.0% 12086 9.0%
imdb 1 2790 snapshot index imdb snap_1 88 7.7% 11025 8.1%
imdb 2 2790 snapshot index imdb snap_1 85 0.0% 12072 0.0%
imdb 3 2796 snapshot index imdb snap_1 85 2.4% 12048 7.2%
imdb 4 819 snapshot init imdb snap_1 0 0.0% 0 0.0%
--------------------------------------------------------------------------------