Data backup and snapshots

It is important to back up a cluster and all the data it contains. We have already talked about replica shards in the previous section. These are not appropriate as a backup, as they do not provide any data protection. Instead, there is a specific API that snapshots and then restores data. The snapshot and restore API is a cluster backup mechanism that saves the current state of the cluster in a repository. We also use the reindex API to make temporary backups when making certain bulk document changes, such as _update_by_query and _delete_by_query. Back up all documents first with _reindex.

There are a few different ways to create a repository for backups. All of the following are supported:

• Shared file systems: fs file type
• Read-only URLs: url file type
• S3: s3 file type
• HDFS: hdfs file type
• Azure: azure file type
• Google Cloud Storage: gcs file type
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