115 lines
5.2 KiB
Plaintext
115 lines
5.2 KiB
Plaintext
[[snapshot-restore]]
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= Snapshot and restore
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[partintro]
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--
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// tag::snapshot-intro[]
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A _snapshot_ is a backup taken from a running {es} cluster.
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You can take snapshots of an entire cluster, including all its data streams and
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indices. You can also take snapshots of only specific data streams or indices in
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the cluster.
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You must
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<<snapshots-register-repository, register a snapshot repository>>
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before you can <<snapshots-take-snapshot, create snapshots>>.
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Snapshots can be stored in either local or remote repositories.
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Remote repositories can reside on Amazon S3, HDFS, Microsoft Azure,
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Google Cloud Storage,
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and other platforms supported by a {plugins}/repository.html[repository plugin].
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Snapshots are incremental: each snapshot only stores data that
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is not part of an earlier snapshot.
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This enables you to take frequent snapshots with minimal overhead.
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// end::snapshot-intro[]
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// tag::restore-intro[]
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You can <<snapshots-restore-snapshot,restore snapshots>> to a running cluster, which includes all data streams and indices in the snapshot
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by default.
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However, you can choose to restore only the cluster state or specific data
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streams or indices from a snapshot.
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// end::restore-intro[]
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You can use
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<<getting-started-snapshot-lifecycle-management, {slm}>>
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to automatically take and manage snapshots.
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// tag::backup-warning[]
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WARNING: You cannot back up an {es} cluster by simply copying
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the data directories of all of its nodes. {es} may be making changes to
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the contents of its data directories while it is running; copying its data
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directories cannot be expected to capture a consistent picture of their contents.
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If you try to restore a cluster from such a backup, it may fail and report
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corruption and/or missing files. Alternatively, it may appear to have succeeded
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though it silently lost some of its data. The only reliable way to back up a
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cluster is by using the snapshot and restore functionality.
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// end::backup-warning[]
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[discrete]
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[[snapshot-restore-version-compatibility]]
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=== Version compatibility
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IMPORTANT: Version compatibility refers to the underlying Lucene index
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compatibility. Follow the <<setup-upgrade,Upgrade documentation>>
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when migrating between versions.
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A snapshot contains a copy of the on-disk data structures that comprise an
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index or a data stream's backing indices. This means that snapshots can only be restored to versions of
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{es} that can read the indices.
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The following table indicates snapshot compatibility between versions. The first column denotes the base version that you can restore snapshots from.
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// tag::snapshot-compatibility-matrix[]
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[cols="6"]
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|===
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| 5+^h| Cluster version
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^h| Snapshot version ^| 2.x ^| 5.x ^| 6.x ^| 7.x ^| 8.x
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^| *1.x* -> ^|{yes-icon} ^|{no-icon} ^|{no-icon} ^|{no-icon} ^|{no-icon}
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^| *2.x* -> ^|{yes-icon} ^|{yes-icon} ^|{no-icon} ^|{no-icon} ^|{no-icon}
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^| *5.x* -> ^|{no-icon} ^|{yes-icon} ^|{yes-icon} ^|{no-icon} ^|{no-icon}
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^| *6.x* -> ^|{no-icon} ^|{no-icon} ^|{yes-icon} ^|{yes-icon} ^|{no-icon}
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^| *7.x* -> ^|{no-icon} ^|{no-icon} ^|{no-icon} ^|{yes-icon} ^|{yes-icon}
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|===
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// end::snapshot-compatibility-matrix[]
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The following conditions apply for restoring snapshots and indices across versions:
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* *Snapshots*: You cannot restore snapshots from later {es} versions into a cluster running an earlier {es} version. For example, you cannot restore a snapshot taken in 7.6.0 to a cluster running 7.5.0.
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* *Indices*: You cannot restore indices into a cluster running a version of {es} that is more than _one major version_ newer than the version of {es} used to snapshot the indices. For example, you cannot restore indices from a snapshot taken in 5.0 to a cluster running 7.0.
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+
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[NOTE]
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====
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The one caveat is that snapshots taken by {es} 2.0 can be restored in clusters running {es} 5.0.
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====
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Each snapshot can contain indices created in various versions of {es}. This
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includes backing indices created for data streams. When restoring a snapshot, it
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must be possible to restore all of these indices into the target cluster. If any
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indices in a snapshot were created in an incompatible version, you will not be
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able restore the snapshot.
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IMPORTANT: When backing up your data prior to an upgrade, keep in mind that you
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won't be able to restore snapshots after you upgrade if they contain indices
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created in a version that's incompatible with the upgrade version.
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If you end up in a situation where you need to restore a snapshot of a data stream or index
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that is incompatible with the version of the cluster you are currently running,
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you can restore it on the latest compatible version and use
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<<reindex-from-remote,reindex-from-remote>> to rebuild the data stream or index on the current
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version. Reindexing from remote is only possible if the original data stream or index has
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source enabled. Retrieving and reindexing the data can take significantly
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longer than simply restoring a snapshot. If you have a large amount of data, we
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recommend testing the reindex from remote process with a subset of your data to
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understand the time requirements before proceeding.
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--
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include::register-repository.asciidoc[]
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include::take-snapshot.asciidoc[]
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include::restore-snapshot.asciidoc[]
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include::monitor-snapshot-restore.asciidoc[]
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include::delete-snapshot.asciidoc[]
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include::../slm/index.asciidoc[]
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