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S3 snapshot overview

Contributors netapp-manini netapp-dbagwell
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Beginning with ONTAP 9.16.1, you can use ONTAP snapshot technology to generate read-only, point-in-time images of your ONTAP S3 buckets.

Using the S3 snapshots feature, you can manually create snapshots or automatically generate them through snapshot policies. S3 snapshots are presented as S3 buckets to S3 clients. You can browse and restore the content from the snapshots through S3 clients.

In ONTAP 9.16.1, S3 snapshots only capture the current versions of the objects in S3 buckets. The non-current versions of versioned buckets are not captured in the S3 snapshots. Also, the point-in-time object tags are not captured in the snapshots if the object tags are modified after the snapshots are taken.

Tip S3 snapshots rely on the cluster time. You should configure the NTP server in your cluster to synchronize the time. For more information, refer to Manage the cluster time.
Quota and space usage

Quotas track the number of objects and logical size used in an S3 bucket. When S3 snapshots are created, the objects captured in the S3 snapshots are counted towards the bucket object count and size used, until the snapshots are deleted from the file system.

Multipart objects

For multipart objects, only the final objects are captured in snapshots. Partial uploads of multipart objects are not captured in snapshots.

Snapshots on versioned and non-versioned buckets

You can create snapshots on both versioned and non-versioned buckets. The snapshot contains only the current object versions at a time when the snapshot is captured.

Versioned buckets and snapshots

In buckets with object versioning enabled, a snapshot retains the content of the most recent object version after which the snapshot was taken. It excludes non-current versions in the bucket.

Consider this example: In a bucket where object versioning is enabled, object obj1 has versions v1, v2, v3, v4, v5. You created a snapshot snap1 from obj1 v3 (the most recent version at the point of capture). When browsing snap1, obj1 will appear as an object with content created at v3. Content of the previous versions will not be returned.

Note The non-current versions are retained in the filesystem, until the snapshots are deleted.
Non-versioned buckets and snapshots

In non-versioned buckets, S3 snapshots preserve the content of the latest commits prior to the snapshot creation.

Consider this example: In a bucket where object versioning is unavailable, object obj1 has been overwritten several times at (t1, t2, t3, t4, and t5). You created an S3 snapshot snap1 sometime between t3 and t4. When browsing snap1, obj1 will appear with the content created at t3.

Object expiration and snapshots

ONTAP S3 object expiration and S3 snapshots feature function independently of each other. ONTAP object expiration feature expires object versions according to the lifecycle management rules defined for the S3 bucket. S3 snapshots are static copies of the bucket objects at a point in time when the snapshot is created.

If object versioning is enabled in a bucket, when a specific version of an object is deleted due to an expiration rule defined for that bucket, the content of the expired object version continues to remain in the filesystem if the version has been captured as a current version in one or more S3 snapshots. That object version will cease to exist in the file system only when that snapshot is deleted.

Similarly, in a bucket in which versioning is disabled, if an object is deleted based on an expiration rule, but the object is still captured in some existing S3 snapshots, the object will be retained in the file system. The object will be permanently removed from the file system when the snapshots capturing it are deleted.

For information about S3 object expiration and lifecycle management, refer to Create a bucket lifecycle management rule.

Limitations with S3 snapshots

Note the following feature exclusions and scenarios in ONTAP 9.16.1:

  • You can generate up to 1023 snapshots for an S3 bucket.

  • It is necessary to delete all the S3 snapshots and metadata from all the buckets in a cluster before reverting the cluster to an ONTAP version earlier than ONTAP 9.16.1.

  • If you need to delete an S3 bucket containing objects with snapshots, ensure that you have deleted all the corresponding snapshots of all the objects in that bucket.

  • S3 snapshots are not supported in these configurations:

    • On buckets in a SnapMirror relationship

    • On buckets where object-locking is enabled

    • On NetApp BlueXP

    • On System Manager

    • In ONTAP MetroCluster configurations