207 lines
9.6 KiB
Plaintext
207 lines
9.6 KiB
Plaintext
[[modules-snapshots]]
|
|
== Snapshot And Restore
|
|
|
|
The snapshot and restore module allows to create snapshots of individual indices or an entire cluster into a remote
|
|
repository. At the time of the initial release only shared file system repository is supported.
|
|
|
|
[float]
|
|
=== Repositories
|
|
|
|
Before any snapshot or restore operation can be performed a snapshot repository should be registered in
|
|
Elasticsearch. The following command registers a shared file system repository with the name `my_backup` that
|
|
will use location `/mount/backups/my_backup` to store snapshots.
|
|
|
|
[source,js]
|
|
-----------------------------------
|
|
$ curl -XPUT 'http://localhost:9200/_snapshot/my_backup' -d '{
|
|
"type": "fs",
|
|
"settings": {
|
|
"location": "/mount/backups/my_backup",
|
|
"compress": true
|
|
}
|
|
}'
|
|
-----------------------------------
|
|
|
|
Once repository is registered, its information can be obtained using the following command:
|
|
|
|
[source,js]
|
|
-----------------------------------
|
|
$ curl -XGET 'http://localhost:9200/_snapshot/my_backup?pretty'
|
|
-----------------------------------
|
|
[source,js]
|
|
-----------------------------------
|
|
{
|
|
"my_backup" : {
|
|
"type" : "fs",
|
|
"settings" : {
|
|
"compress" : "false",
|
|
"location" : "/mount/backups/my_backup"
|
|
}
|
|
}
|
|
}
|
|
-----------------------------------
|
|
|
|
If a repository name is not specified, or `_all` is used as repository name Elasticsearch will return information about
|
|
all repositories currently registered in the cluster:
|
|
|
|
[source,js]
|
|
-----------------------------------
|
|
$ curl -XGET 'http://localhost:9200/_snapshot'
|
|
-----------------------------------
|
|
|
|
or
|
|
|
|
[source,js]
|
|
-----------------------------------
|
|
$ curl -XGET 'http://localhost:9200/_snapshot/_all'
|
|
-----------------------------------
|
|
|
|
[float]
|
|
===== Shared File System Repository
|
|
|
|
The shared file system repository (`"type": "fs"`) is using shared file system to store snapshot. The path
|
|
specified in the `location` parameter should point to the same location in the shared filesystem and be accessible
|
|
on all data and master nodes. The following settings are supported:
|
|
|
|
[horizontal]
|
|
`location`:: Location of the snapshots. Mandatory.
|
|
`compress`:: Turns on compression of the snapshot files. Defaults to `true`.
|
|
`concurrent_streams`:: Throttles the number of streams (per node) preforming snapshot operation. Defaults to `5`
|
|
`chunk_size`:: Big files can be broken down into chunks during snapshotting if needed. The chunk size can be specified in bytes or by
|
|
using size value notation, i.e. 1g, 10m, 5k. Defaults to `null` (unlimited chunk size).
|
|
`max_restore_bytes_per_sec`:: Throttles per node restore rate. Defaults to `20mb` per second.
|
|
`max_snapshot_bytes_per_sec`:: Throttles per node snapshot rate. Defaults to `20mb` per second.
|
|
|
|
|
|
[float]
|
|
===== Read-only URL Repository
|
|
|
|
The URL repository (`"type": "url"`) can be used as an alternative read-only way to access data created by shared file
|
|
system repository is using shared file system to store snapshot. The URL specified in the `url` parameter should
|
|
point to the root of the shared filesystem repository. The following settings are supported:
|
|
|
|
[horizontal]
|
|
`url`:: Location of the snapshots. Mandatory.
|
|
`concurrent_streams`:: Throttles the number of streams (per node) preforming snapshot operation. Defaults to `5`
|
|
|
|
|
|
[float]
|
|
===== Repository plugins
|
|
|
|
Other repository backends are available in these official plugins:
|
|
|
|
* https://github.com/elasticsearch/elasticsearch-cloud-aws#s3-repository[AWS Cloud Plugin] for S3 repositories
|
|
* https://github.com/elasticsearch/elasticsearch-hadoop/tree/master/repository-hdfs[HDFS Plugin] for Hadoop environments
|
|
|
|
[float]
|
|
=== Snapshot
|
|
|
|
A repository can contain multiple snapshots of the same cluster. Snapshot are identified by unique names within the
|
|
cluster. A snapshot with the name `snapshot_1` in the repository `my_backup` can be created by executing the following
|
|
command:
|
|
|
|
[source,js]
|
|
-----------------------------------
|
|
$ curl -XPUT "localhost:9200/_snapshot/my_backup/snapshot_1?wait_for_completion=true"
|
|
-----------------------------------
|
|
|
|
The `wait_for_completion` parameter specifies whether or not the request should return immediately or wait for snapshot
|
|
completion. By default snapshot of all open and started indices in the cluster is created. This behavior can be changed
|
|
by specifying the list of indices in the body of the snapshot request.
|
|
|
|
[source,js]
|
|
-----------------------------------
|
|
$ curl -XPUT "localhost:9200/_snapshot/my_backup/snapshot_1" -d '{
|
|
"indices": "index_1,index_2",
|
|
"ignore_unavailable": "true",
|
|
"include_global_state": false
|
|
}'
|
|
-----------------------------------
|
|
|
|
The list of indices that should be included into the snapshot can be specified using the `indices` parameter that
|
|
supports <<search-multi-index-type,multi index syntax>>. The snapshot request also supports the
|
|
`ignore_unavailable` option. Setting it to `true` will cause indices that do not exists to be ignored during snapshot
|
|
creation. By default, when `ignore_unavailable` option is not set and an index is missing the snapshot request will fail.
|
|
By setting `include_global_state` to false it's possible to prevent the cluster global state to be stored as part of
|
|
the snapshot. By default, entire snapshot will fail if one or more indices participating in the snapshot don't have
|
|
all primary shards available. This behaviour can be changed by setting `partial` to `true`.
|
|
|
|
The index snapshot process is incremental. In the process of making the index snapshot Elasticsearch analyses
|
|
the list of the index files that are already stored in the repository and copies only files that were created or
|
|
changed since the last snapshot. That allows multiple snapshots to be preserved in the repository in a compact form.
|
|
Snapshotting process is executed in non-blocking fashion. All indexing and searching operation can continue to be
|
|
executed against the index that is being snapshotted. However, a snapshot represents the point-in-time view of the index
|
|
at the moment when snapshot was created, so no records that were added to the index after snapshot process had started
|
|
will be present in the snapshot.
|
|
|
|
Besides creating a copy of each index the snapshot process can also store global cluster metadata, which includes persistent
|
|
cluster settings and templates. The transient settings and registered snapshot repositories are not stored as part of
|
|
the snapshot.
|
|
|
|
Only one snapshot process can be executed in the cluster at any time. While snapshot of a particular shard is being
|
|
created this shard cannot be moved to another node, which can interfere with rebalancing process and allocation
|
|
filtering. Once snapshot of the shard is finished Elasticsearch will be able to move shard to another node according
|
|
to the current allocation filtering settings and rebalancing algorithm.
|
|
|
|
Once a snapshot is created information about this snapshot can be obtained using the following command:
|
|
|
|
[source,shell]
|
|
-----------------------------------
|
|
$ curl -XGET "localhost:9200/_snapshot/my_backup/snapshot_1"
|
|
-----------------------------------
|
|
|
|
All snapshots currently stored in the repository can be listed using the following command:
|
|
|
|
[source,shell]
|
|
-----------------------------------
|
|
$ curl -XGET "localhost:9200/_snapshot/my_backup/_all"
|
|
-----------------------------------
|
|
|
|
A snapshot can be deleted from the repository using the following command:
|
|
|
|
[source,shell]
|
|
-----------------------------------
|
|
$ curl -XDELETE "localhost:9200/_snapshot/my_backup/snapshot_1"
|
|
-----------------------------------
|
|
|
|
When a snapshot is deleted from a repository, Elasticsearch deletes all files that are associated with the deleted
|
|
snapshot and not used by any other snapshots. If the deleted snapshot operation is executed while the snapshot is being
|
|
created the snapshotting process will be aborted and all files created as part of the snapshotting process will be
|
|
cleaned. Therefore, the delete snapshot operation can be used to cancel long running snapshot operations that were
|
|
started by mistake.
|
|
|
|
|
|
[float]
|
|
=== Restore
|
|
|
|
A snapshot can be restored using this following command:
|
|
|
|
[source,shell]
|
|
-----------------------------------
|
|
$ curl -XPOST "localhost:9200/_snapshot/my_backup/snapshot_1/_restore"
|
|
-----------------------------------
|
|
|
|
By default, all indices in the snapshot as well as cluster state are restored. It's possible to select indices that
|
|
should be restored as well as prevent global cluster state from being restored by using `indices` and
|
|
`include_global_state` options in the restore request body. The list of indices supports
|
|
<<search-multi-index-type,multi index syntax>>. The `rename_pattern` and `rename_replacement` options can be also used to
|
|
rename index on restore using regular expression that supports referencing the original text as explained
|
|
http://docs.oracle.com/javase/6/docs/api/java/util/regex/Matcher.html#appendReplacement(java.lang.StringBuffer,%20java.lang.String)[here].
|
|
|
|
[source,js]
|
|
-----------------------------------
|
|
$ curl -XPOST "localhost:9200/_snapshot/my_backup/snapshot_1/_restore" -d '{
|
|
"indices": "index_1,index_2",
|
|
"ignore_unavailable": "true",
|
|
"include_global_state": false,
|
|
"rename_pattern": "index_(.)+",
|
|
"rename_replacement": "restored_index_$1"
|
|
}'
|
|
-----------------------------------
|
|
|
|
The restore operation can be performed on a functioning cluster. However, an existing index can be only restored if it's
|
|
closed. 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, 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.
|