The only reliable and supported way to back up a cluster is by taking a snapshot. You cannot back up an Elasticsearch cluster by making copies of the data directories of its nodes. There are no supported methods to restore any data from a filesystem-level backup. If you try to restore a cluster from such a backup, it may fail with reports of corruption or missing files or other data inconsistencies, or it may appear to have succeeded having silently lost some of your data.
To have a complete backup for your cluster:
To restore your cluster from a backup: