Questions about ES snapshot/restore

[shrenikgala (Shrenik)]

I'm using Elasticsearch 2.4.4 and need to use the snapshot/restore mechanism to backup data. But I have a few questions about it.

1. Can a snapshot be taken without any issues while data is being written into ES. 
2. Does it matter which of master/data/client node is being used for taking snapshots. 
3.Does restore require indices to be closed.If yes then why

[raulk89 (Raul Kaubi)]

Hi

1. Yes, although I am using version 1.7.2 in production, and I am taking snapshots every hour, with no problem at all, it just may take a little CPU resources and disk I/O, but other than that works fine.
2. My bet would be no. Though I am using current master node for this operation. But it should be fine, if done from another node.
3. Yes, indices needs to be closed, my bet would be that, restore operation can't handle "posting new documents into indices", while these are being restored.
   Read here: https://www.elastic.co/guide/en/elasticsearch/reference/2.4/modules-snapshots.html

The restore operation can be performed on a functioning cluster. However, an existing index can be only restored if it’s closed and has the same number of shards as the index in the snapshot. The restore operation automatically opens restored indices if they were closed and creates new indices if they didn’t exist in the cluster. If cluster state is restored with include_global_state (defaults to false), the restored templates that don’t currently exist in the cluster are added and existing templates with the same name are replaced by the restored templates. The restored persistent settings are added to the existing persistent settings.

Regards
Raul