Scaling down ElasticSearch: what happens with closed indices?

To scale down ElasticSearch, I usually disable allocation on a node, wait for shards to relocate, and then remove the node, e.g.:

curl -X PUT "localhost:9200/_cluster/settings" -d'{
  "transient" : {
    "cluster.routing.allocation.exclude._name" : "node-4"

As I understand, open indices' shards will be relocated to other nodes... but what happens to closed indices?

A closed index is, per my understanding, ignored on snapshots... so it makes me think if it will be ignored when setting an allocation exclusion as well.

After excluding allocation to a node, I went to check its disk usage... and it seems like it still has a lot of things there:

$ du -hs /usr/share/elasticsearch/nodes/0/
131G	/usr/share/elasticsearch/nodes/0/

So, my questions are:

  • What happens to closed indices when I exclude a node from allocation?
  • How safe it is to do this if I don't want to loose those closed indices (for whatever reason)?
  • Is there a way to tell ES to also rebalance closed indices in case it doesn't already do it?

It depends on what version you are on. More recent versions have replicas for closed indices, but I am not 100% sure when that landed.

I am not sure how allocation works for them though sorry.

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Thanks, I'm on 5.6.16... didn't find anything on the docs :frowning:

Ahh ok, yeah that's not going to apply then sorry, that's definitely a later 7.X feature.

I will highlight that 5.X reached EOL some time ago, and you should look at upgrading as a matter of urgency :slight_smile:

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Yes, need to upgrade ASAP, unfortunately also need to redesign a lot of things to do it :thinking: hehe

If you are on Elasticsearch 5.x you will need to open them in order to relocate the shards.

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