About Long Term Retention
Business 
Enterprise Elite The availability of the Long Term Retention (LTR) feature is limited to Enterprise and Elite editions. To access this feature, contact your Druva Account Manager or Druva Support. This article/documentation is subject to change based on the continuous improvements to this feature.
In our day-to-day lives, we like to arrange our books, clothes, and other items in a way that helps us keep the more frequently used ones at an arm’s reach, while the less frequently used ones take a back seat. We call this behavior “being organized” and this sense of organization helps us save some precious time. Now, when you apply the same sense of organization in your data protection with Druva, you not only save time but money too. Say hello to Long Term Retention, or as we like to call it - LTR!
Before using this feature, you must identify the data suitable for long-term retention. This is the data that is important for the business to retain, but you can maintain it at a different location with low maintenance cost. Also, you do not mind a higher RTO for this data, which means a higher tolerable recovery time.
After successfully identifying such data, you can use Druva, which leverages the capabilities of Amazon Glacier Deep Archive (GDA as cold tier) for data protection, and perform the following:
- Reduce your overall data protection cost by 20%.
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Protect data for the long term to address legal and compliance needs.
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Meet your RTO SLAs with the latest backups.
Several pieces are involved in how your data gets to the cold tier and is restored. Let’s take a look at the workflow to know how it works.
Note: Long Term Retention (LTR) is available for Druva Public and GovCloud. However, it is currently not available for AWS Marketplace customers.
Workflow
Here’s what happens:
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You identify the backup sets that protect the data that you deem suitable for long term retention. This is the data that you want to retain for one year or longer and for which the RTO requirement relaxes after 15, 30, 45, and 60 days.
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You buy credits based on your estimation of LTR and Non-LTR data.
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You then set the retention period as one year or more in the backup policy and enable LTR for this policy.
Note: The one-year retention period can be in the form of weekly, monthly, or yearly backups. For example:
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And, then comes the best part! You begin getting the cost benefits on your storage once there is a first transition of Warm snapshots to Cold tier, which depends on the Warm snapshots threshold set on the policy and the policy retention.
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All data in the LTR backup sets consume lower credits.
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Snapshots older than the Warm snapshots threshold of an LTR-enabled backup set are transitioned to the Cold tier.
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At the time of restoring, this data is first retrieved from the cold tier and stored in the warm tier, where it resides temporarily for at most 10 days, and then restored.
On a high level, this is pretty much it! But, to get the most out of this feature, you need to know the details of the eligibility criteria, the data restore process, and early delete fees. Read on to find out!
Terms to know
- Warm snapshots: Warm snapshots are point-in-time copies of backup data for the set no. of days. These snapshots are stored in the Amazon S3 storage. Data from warm snapshots can be restored immediately.
- Cold snapshots: Cold snapshots are point-in-time copies of backup data older than the Warm snapshots threshold. These snapshots are stored in the Amazon Glacier Deep Archive.
The eligibility criterion for LTR
The cold tier is designed to reduce the cost of data that you retain for the long term. Hence, only the backup sets for which the retention period is greater than or equal to one year are eligible for LTR.
Impact on non-LTR backup policies
In short, there is no intelligent tiering for non-LTR backup policies. All the snapshots are stored in the warm tier. You can initiate restoration from non-LTR backup sets regardless of the age of the snapshot.
Restoration of cold-tier data
At the time of restoring, the data from the cold tier is retrieved, moved temporarily to the warm tier, and then restored. Once you click Restore and initiate the restoration process, the data retrieval from the cold tier and its restore from the warm tier happen automatically. Warmed-up data is deleted from the warm tier after 10 days.
RTO for cold data = data retrieve time + data restore time
- Data retrieve time is the time needed to identify the cold blocks and initiate and retrieve data blocks from the cold tier (typically 12-36 hours).
- Data restore time is the time needed to restore the data. This is similar to the restoration of data from the warm tier once the data retrieval process from the cold tier is complete.
LTR savings
When the first snapshot for the LTR-enabled backup sets is moved to cold tier, you begin getting the cost reduction on your credits. This cost reduction is applicable to the total size of the associated backup set(s) post deduplication. Let us explain this to you in detail. Take a look at the following comparison between credit consumption of a backup set with LTR not enabled (A) and a backup set with LTR enabled (B).
| Backup set | LTR enabled? | Data size after deduplication | Credit consumption rate per TB | Credits consumed | Credits savings |
|---|---|---|---|---|---|
| A | No | 100 TB | 1 credit per month | 100 | 0 |
| B | Yes | 100 TB | 0.8 credit per month | 80 | 20 |
As you can see, with the same size of data stored (100 TB), you can save 20 credits in a month by enabling LTR.
Calculation of credit consumption
The formula to calculate the total number of credits consumed for a backup set is as follows:
Credit Consumption (in Credits) = (Deduped backup set data size)* (Credit consumption rate per TB per month)* (number of months the data is retained for)
Early delete fee
If you delete your data before the one-year retention period completes, Druva incurs an early delete cost. Hence, we charge you an early delete fee depending on the size of your data that you deleted early from the cold tier. The early delete fee is recorded in your billing.
Conditions for early delete fee
- An early delete fee will apply if your snapshots get expired due to a reduction of the retention period.
- An early delete fee will apply if you manually delete the cold snapshots, backup sets, or servers with cold snapshots.
Note: Snapshots older than one year (after LTR is enabled) will not incur any early delete fee.
Calculation of early delete fee
We calculate the early delete fee for early deletion of snapshots, backup sets, and servers (provided some or all data resides in the cold tier), and the same would reflect in your billing. Early deletion refers to the data that gets deleted before one year of the retention period. The early delete fee is calculated based on the size of the data that gets deleted from the cold tier earlier than one year.
Early Delete Fee (in credits) = 0.35*(12 - # months in cold tier)*(Data deleted in TB)