Process for Faster Restores from Amazon S3 Glacier

This page describes the restore process for faster restores from Amazon S3 Glacier Flexible Retrieval, which use Amazon S3 Batch Operations to optimize and accelerate the restore operation.


  1. The application owner or cloud ops administrator initiates a restore using Commvault Command Center (CLI or REST API).

Commvault automates the Amazon S3 Glacier Faster Restore. Commvault automatically identifies the Amazon S3 objects that are required to restore the instances and passes those files to the Commvault Cloud Archive Recall workflow. 2. The Cloud Archive Recall workflow synthesizes an S3 Batch Operations CSV format manifest and uploads it to s3BatchOperationsRestore/CVRestoreJobId-nnn/manifest.csv within the S3 bucket (cloud library) that is the source for the restore job.

The manifest file is placed in the S3 Standard storage class. The manifest contains the bucket name as objectkey_to_restore.






Commvault does not specify the (optional) S3 object version in the manifest file. Only the most recent version of each object is used for the recovery.

For the manifest file format, see Specifying a manifest. 3. The Cloud Archive Recall workflow compute node (typically, a Commvault MediaAgent or cloud access node) contacts the S3 Batch Operations regional service endpoint (, and does the following:

  • Submits a new s3:CreateJob request
  • Receives an S3 Batch Operations Job Id

Commvault passes the ConfirmationRequired = false parameter as part of the s3:CreateJob request, no approval in the Amazon S3 Management Console is required to progress the resotre job.

For Amazon S3 Glacier Flexible Retrieval and Amazon S3 Glacier Deep Archive, a Restore Object batch operation creates a temporary copy of each of the objects requested, and then deletes the copy after the ExpirationInDays days have elapsed.

Commvault sets the ExpirationInDays to 7 (use the AutoCloudRecallExpireDays setting to reduce the number of days to reduce storage cost in S3 Glacier Flexible Retrieval and S3 Glacier Deep Archive restores), because the data is not needed after the restore completes. ExpirationInDays in days can be customized by setting the AutoCloudRecallExpireDays entity setting.

Commvault recommends setting the `AutoCloudRecallExpireDays setting to 1 to minimize the storage costs associated with faster restores.

Objects in S3 Intelligent-Tiering archive access tiers are not subject to restore expiration.

For more information, see Restoring objects from the S3 Intelligent-Tiering Archive Access and Deep Archive Access tiers.


When you restore an archived object from S3 Glacier Flexible Retrieval or S3 Glacier Deep Archive, you pay for both the archive and a copy that you restored temporarily. For more information about pricing, see Amazon S3 pricing.

  1. The Cloud Archive Recall workflow polls the Amazon S3 objects strategically by periodically running a HEAD Object (s3:HeadObject) against one object in each batch, until all objects are restored.

The default polling interval is 20 minutes (4 hours) and can be customized using the nCloudChunkRecallSleepIntervalMins entity setting.

Commvault has performed testing of restore performance using Amazon S3 Glacier Faster Restores and found the following polling intervals to be optimal to minimize restore time.

  • S3 Glacier Flexible Retrieval: 15 minutes (default is 20 minutes)
  • S3 Glacier Deep Archive: 540 (default is 20 minutes)

The x-amz-restore field that is returned by s3:HeadObject shows whether a restore activity is currently in progress for the object or is completed with the expiry timer started:

x-amz-restore: ongoing-request="false", expiry-date="Fri, 21 Dec 2012 00:00:00 GMT"

If the object restoration is in progress, the header returns the value ongoing-request="true". For more information, see s3:HeadObject – Response Elements (x-amz-restore). 5. The Cloud Archive Recall workflow returns the success to the Commvault Job Manager, which then continues to restore the compute or containerized instance to the preferred location.