OpenSearch/docs/reference/cat/recovery.asciidoc

[[cat-recovery]]
== Recovery

`recovery` is a view of shard replication.  It will show information
anytime data from at least one shard is copying to a different node.
It can also show up on cluster restarts.  If your recovery process
seems stuck, try it to see if there's any movement.

As an example, let's enable replicas on a cluster which has two
indices, three shards each.  Afterward we'll have twelve total shards,
but before those replica shards are `STARTED`, we'll take a snapshot
of the recovery:

[source,shell]
--------------------------------------------------
% curl -XPUT 192.168.56.30:9200/_settings -d'{"number_of_replicas":1}'
{"acknowledged":true}
% curl '192.168.56.30:9200/_cat/recovery?v'
index shard   target recovered     % ip            node
wiki1 2     68083830   7865837 11.6% 192.168.56.20 Adam II
wiki2 1      2542400    444175 17.5% 192.168.56.20 Adam II
wiki2 2      3242108    329039 10.1% 192.168.56.10 Jarella
wiki2 0      2614132         0  0.0% 192.168.56.30 Solarr
wiki1 0     60992898   4719290  7.7% 192.168.56.30 Solarr
wiki1 1     47630362   6798313 14.3% 192.168.56.10 Jarella
--------------------------------------------------

We have six total shards in recovery (a replica for each primary), at
varying points of progress.

Let's restart the cluster and then lose a node.  This output shows us
what was moving around shortly after the node left the cluster.

[source,shell]
--------------------------------------------------
% curl 192.168.56.30:9200/_cat/health; curl 192.168.56.30:9200/_cat/recovery
1384315040 19:57:20 foo yellow 2 2 8 6 0 4 0
wiki2 2  1621477        0  0.0% 192.168.56.30 Garrett, Jonathan "John"
wiki2 0  1307488        0  0.0% 192.168.56.20 Commander Kraken
wiki1 0 32696794 20984240 64.2% 192.168.56.20 Commander Kraken
wiki1 1 31123128 21951695 70.5% 192.168.56.30 Garrett, Jonathan "John"
--------------------------------------------------

[float]
[[big-percent]]
=== Why am I seeing recovery percentages greater than 100?

This can happen if a shard copy goes away and comes back while the
primary was indexing.  The replica shard will catch up with the
primary by receiving any new segments created during its outage.
These new segments can contain data from segments it already has
because they're the result of merging that happened on the primary,
but now live in different, larger segments.  After the new segments
are copied over the replica will delete unneeded segments, resulting
in a dataset that more closely matches the primary (or exactly,
assuming indexing isn't still happening).