[[snapshots-register-repository]]
== Register a snapshot repository

++++
<titleabbrev>Register repository</titleabbrev>
++++
[[snapshots-register-repository-description]]
// tag::snapshots-register-repository-tag[]
You must register a snapshot repository before you can perform snapshot and
restore operations. Use the <<put-snapshot-repo-api,put snapshot repository API>> to register or update a snapshot repository. We recommend creating a new snapshot repository for each
major version. The valid repository settings depend on the repository type.

If you register the 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.
// end::snapshots-register-repository-tag[]

[IMPORTANT]
====
The snapshot format can change across major versions, so if you have
clusters on different versions trying to write to 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.
====

[source,console]
-----------------------------------
PUT /_snapshot/my_backup
{
  "type": "fs",
  "settings": {
    "location": "my_backup_location"
  }
}
-----------------------------------
// TESTSETUP

Use the <<get-snapshot-api,get snapshot API>> to retrieve information about a registered repository:

[source,console]
-----------------------------------
GET /_snapshot/my_backup
-----------------------------------

This request returns the following response:

[source,console-result]
-----------------------------------
{
  "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 a 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`:

[source,console]
-----------------------------------
GET /_snapshot/repo*,*backup*
-----------------------------------

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

[source,console]
-----------------------------------
GET /_snapshot
-----------------------------------

Alternatively, you can specify `_all`:

[source,console]
-----------------------------------
GET /_snapshot/_all
-----------------------------------

You can unregister a repository using the
<<delete-snapshot-repo-api,delete snapshot repository API>>:

[source,console]
-----------------------------------
DELETE /_snapshot/my_backup
-----------------------------------

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

[discrete]
[[snapshots-filesystem-repository]]
=== 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:

[source,yaml]
--------------
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:

[source,yaml]
--------------
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`:

[source,console]
-----------------------------------
PUT /_snapshot/my_fs_backup
{
  "type": "fs",
  "settings": {
    "location": "/mount/backups/my_fs_backup_location",
    "compress": true
  }
}
-----------------------------------
// TEST[skip:no access to absolute path]

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

[source,console]
-----------------------------------
PUT /_snapshot/my_fs_backup
{
  "type": "fs",
  "settings": {
    "location": "my_fs_backup_location",
    "compress": true
  }
}
-----------------------------------
// TEST[continued]

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 unlimited. Note that restores are also throttled through <<recovery,recovery settings>>.
`max_snapshot_bytes_per_sec`:: Throttles per node snapshot rate. Defaults to `40mb` per second.
`readonly`:: Makes repository read-only.  Defaults to `false`.

[discrete]
[[snapshots-read-only-repository]]
=== 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.

[source,console]
----
PUT /_snapshot/my_read_only_url_repository
{
  "type": "url",
  "settings": {
    "url": "file:/mount/backups/my_fs_backup_location"
  }
}
----
// TEST[skip:no access to url file path]

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
<<snapshots-filesystem-repository,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:

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

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

[discrete]
[role="xpack"]
[testenv="basic"]
[[snapshots-source-only-repository]]
=== 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 <<docs-reindex,reindex>>
the data into a new index.

Source repositories delegate to another snapshot repository for storage.

[IMPORTANT]
==================================================

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:

[source,console]
-----------------------------------
PUT _snapshot/my_src_only_repository
{
  "type": "source",
  "settings": {
    "delegate_type": "fs",
    "location": "my_backup_location"
  }
}
-----------------------------------
// TEST[continued]

[discrete]
[[snapshots-repository-plugins]]
=== Repository plugins

Other repository backends are available in these official plugins:

* {plugins}/repository-s3.html[repository-s3] for S3 repository support
* {plugins}/repository-hdfs.html[repository-hdfs] for HDFS repository support in Hadoop environments
* {plugins}/repository-azure.html[repository-azure] for Azure storage repositories
* {plugins}/repository-gcs.html[repository-gcs] for Google Cloud Storage repositories

[discrete]
[[snapshots-repository-verification]]
=== 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:

[source,console]
-----------------------------------
PUT /_snapshot/my_unverified_backup?verify=false
{
  "type": "fs",
  "settings": {
    "location": "my_unverified_backup_location"
  }
}
-----------------------------------
// TEST[continued]

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

[source,console]
-----------------------------------
POST /_snapshot/my_unverified_backup/_verify
-----------------------------------
// TEST[continued]

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

[discrete]
[[snapshots-repository-cleanup]]
=== 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.

[source,console]
-----------------------------------
POST /_snapshot/my_repository/_cleanup
-----------------------------------
// TEST[continued]

The response to a cleanup request looks as follows:

[source,console-result]
--------------------------------------------------
{
  "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.
