Register a snapshot repository

You must register a snapshot repository before you can perform snapshot and restore operations. We recommend creating a new snapshot repository for each major version. The valid repository settings depend on the repository type.

If you register same snapshot repository with multiple clusters, only one cluster should have write access to the repository. All other clusters connected to that repository should set the repository to readonly mode.

The snapshot format can change across major versions, so if you have clusters on different versions trying to write the same repository, snapshots written by one version may not be visible to the other and the repository could be corrupted. While setting the repository to readonly on all but one of the clusters should work with multiple clusters differing by one major version, it is not a supported configuration.

PUT /_snapshot/my_backup
{
  "type": "fs",
  "settings": {
    "location": "my_backup_location"
  }
}

To retrieve information about a registered repository, use a GET request:

GET /_snapshot/my_backup

which returns:

{
  "my_backup": {
    "type": "fs",
    "settings": {
      "location": "my_backup_location"
    }
  }
}

To retrieve information about multiple repositories, specify a comma-delimited list of repositories. You can also use the * wildcard when specifying repository names. For example, the following request retrieves information about all of the snapshot repositories that start with repo or contain backup:

GET /_snapshot/repo*,*backup*

To retrieve information about all registered snapshot repositories, omit the repository name or specify _all:

GET /_snapshot

or

GET /_snapshot/_all

You can unregister a repository using the delete snapshot repository API:

DELETE /_snapshot/my_backup

When a repository is unregistered, Elasticsearch only removes the reference to the location where the repository is storing the snapshots. The snapshots themselves are left untouched and in place.

Shared file system repository

The shared file system repository ("type": "fs") uses the shared file system to store snapshots. In order to register the shared file system repository it is necessary to mount the same shared filesystem to the same location on all master and data nodes. This location (or one of its parent directories) must be registered in the path.repo setting on all master and data nodes.

Assuming that the shared filesystem is mounted to /mount/backups/my_fs_backup_location, the following setting should be added to elasticsearch.yml file:

path.repo: ["/mount/backups", "/mount/longterm_backups"]

The path.repo setting supports Microsoft Windows UNC paths as long as at least server name and share are specified as a prefix and back slashes are properly escaped:

path.repo: ["\\\\MY_SERVER\\Snapshots"]

After all nodes are restarted, the following command can be used to register the shared file system repository with the name my_fs_backup:

PUT /_snapshot/my_fs_backup
{
    "type": "fs",
    "settings": {
        "location": "/mount/backups/my_fs_backup_location",
        "compress": true
    }
}

If the repository location is specified as a relative path this path will be resolved against the first path specified in path.repo:

PUT /_snapshot/my_fs_backup
{
    "type": "fs",
    "settings": {
        "location": "my_fs_backup_location",
        "compress": true
    }
}

The following settings are supported:

location

Location of the snapshots. Mandatory.

compress

Turns on compression of the snapshot files. Compression is applied only to metadata files (index mapping and settings). Data files are not compressed. Defaults to true.

chunk_size

Big files can be broken down into chunks during snapshotting if needed. Specify the chunk size as a value and unit, for example: 1GB, 10MB, 5KB, 500B. Defaults to null (unlimited chunk size).

max_restore_bytes_per_sec

Throttles per node restore rate. Defaults to 40mb per second.

max_snapshot_bytes_per_sec

Throttles per node snapshot rate. Defaults to 40mb per second.

readonly

Makes repository read-only. Defaults to false.

Read-only URL repository

If you register the same snapshot repository with multiple clusters, only one cluster should have write access to the repository. Having multiple clusters write to the repository at the same time risks corrupting the contents of the repository.

To reduce this risk, you can use URL repositories ("type": "url") to give one or more clusters read-only access to a shared file system repository. As URL repositories are always read-only, they are a safer and more convenient alternative to registering a read-only shared filesystem repository.

The URL specified in the url parameter should point to the root of the shared filesystem repository.

PUT /_snapshot/my_read_only_url_repository
{
  "type": "url",
  "settings": {
    "url": "file:/mount/backups/my_fs_backup_location"
  }
}

The url parameter supports the following protocols:

  • file
  • ftp
  • http
  • https
  • jar

URLs using the file protocol must point to the location of a shared filesystem accessible to all master and data nodes in the cluster. This location must be registered in the path.repo setting, similar to a shared file system repository.

URLs using the ftp, http, or https protocols must be explicitly allowed with the repositories.url.allowed_urls setting. This setting supports wildcards (*) in place of a host, path, query, or fragment in the URL. For example:

repositories.url.allowed_urls: ["http://www.example.org/root/*", "https://*.mydomain.com/*?*#*"]

URLs using the ftp, http, https, or jar protocols do not need to be registered in the path.repo setting.

Source only repository

A source repository enables you to create minimal, source-only snapshots that take up to 50% less space on disk. Source only snapshots contain stored fields and index metadata. They do not include index or doc values structures and are not searchable when restored. After restoring a source-only snapshot, you must reindex the data into a new index.

Source repositories delegate to another snapshot repository for storage.

Source only snapshots are only supported if the _source field is enabled and no source-filtering is applied. When you restore a source only snapshot:

  • The restored index is read-only and can only serve match_all search or scroll requests to enable reindexing.
  • Queries other than match_all and _get requests are not supported.
  • The mapping of the restored index is empty, but the original mapping is available from the types top level meta element.

When you create a source repository, you must specify the type and name of the delegate repository where the snapshots will be stored:

PUT _snapshot/my_src_only_repository
{
  "type": "source",
  "settings": {
    "delegate_type": "fs",
    "location": "my_backup_location"
  }
}

Repository plugins

Other repository backends are available in these official plugins:

Repository verification

When a repository is registered, it’s immediately verified on all master and data nodes to make sure that it is functional on all nodes currently present in the cluster. The verify parameter can be used to explicitly disable the repository verification when registering or updating a repository:

PUT /_snapshot/my_unverified_backup?verify=false
{
  "type": "fs",
  "settings": {
    "location": "my_unverified_backup_location"
  }
}

The verification process can also be executed manually by running the following command:

POST /_snapshot/my_unverified_backup/_verify

It returns a list of nodes where repository was successfully verified or an error message if verification process failed.

Repository cleanup

Repositories can over time accumulate data that is not referenced by any existing snapshot. This is a result of the data safety guarantees the snapshot functionality provides in failure scenarios during snapshot creation and the decentralized nature of the snapshot creation process. This unreferenced data does in no way negatively impact the performance or safety of a snapshot repository but leads to higher than necessary storage use. In order to clean up this unreferenced data, users can call the cleanup endpoint for a repository which will trigger a complete accounting of the repositories contents and subsequent deletion of all unreferenced data that was found.

POST /_snapshot/my_repository/_cleanup

The response to a cleanup request looks as follows:

{
  "results": {
    "deleted_bytes": 20,
    "deleted_blobs": 5
  }
}

Depending on the concrete repository implementation the numbers shown for bytes free as well as the number of blobs removed will either be an approximation or an exact result. Any non-zero value for the number of blobs removed implies that unreferenced blobs were found and subsequently cleaned up.

Please note that most of the cleanup operations executed by this endpoint are automatically executed when deleting any snapshot from a repository. If you regularly delete snapshots, you will in most cases not get any or only minor space savings from using this functionality and should lower your frequency of invoking it accordingly.