Amazon EBS Encryption and Snapshot Sharing - Cross-Account and Cross-Region Design
A comprehensive guide covering default encryption setup, cross-account snapshot sharing, and cross-region copy for DR design.
EBS Default Encryption
Enabling EBS default encryption in the account's regional settings automatically encrypts all new EBS volumes and snapshots created in that region. Existing unencrypted volumes are not affected. You can choose between an AWS managed key (aws/ebs) or a customer managed key (CMK) for encryption. Using a CMK allows you to control access through key policies and enable automatic key rotation. The performance impact of encryption is negligible; on Nitro-based instances, hardware acceleration reduces the encryption overhead to near zero.
Cross-Account Snapshot Sharing
EBS snapshots can be shared with other AWS accounts. Unencrypted snapshots can be shared simply by specifying the account ID, but sharing encrypted snapshots requires additional configuration. You must grant the target account kms:DescribeKey, kms:CreateGrant, and kms:Decrypt permissions in the KMS key policy used for encryption. Snapshots encrypted with the AWS managed key (aws/ebs) cannot be shared, so if cross-account sharing is planned, encrypt with a CMK. When the target account creates a volume from the shared snapshot, it is recommended to re-encrypt with their own KMS key.
Cross-Region Copy and DR
Cross-region snapshot copy is a fundamental DR technique. When you enable cross-region copy in a DLM policy, DLM automatically runs the copy to the DR region at the same time as it creates the daily snapshot. You can also set the number of retained generations in the destination region separately, which enables cost optimization such as keeping only the three most recent generations in the DR region. The snapshot archive feature moves snapshots that you retain for 90 days or more to a low-cost archive tier and can reduce costs by up to 75% compared with standard storage. Restoring from the archive takes up to 72 hours, so keep snapshots that need immediate recovery in the standard tier.
EBS Snapshot Pricing
EBS snapshots use incremental backups, storing only changed blocks. Storage costs approximately USD 0.05 per GB/month (as of August 2026). Cross-region copies incur storage costs in the destination region plus inter-region data transfer fees (approximately USD 0.02 per GB). Automate snapshot creation and deletion with DLM (Data Lifecycle Manager) and set appropriate retention periods to manage storage costs. EBS Snapshots Archive costs approximately USD 0.0125 per GB/month, reducing costs by 75% for snapshots retained 90 days or longer.
How Encryption Works and Key Management
EBS encryption transparently encrypts the data that you store on a volume and the snapshots that you take from it. Encryption and decryption run automatically in the background, so the application side needs no special processing. You manage the keys for encryption in KMS and use permissions to control who can decrypt with those keys. If you enable default encryption for the entire account, new volumes that you create become encrypted automatically, so you can avoid volumes left unencrypted. Designing key management and access control properly is the core of protecting stored data.
Snapshot Operations and Lifecycle
Taking and managing snapshots by hand takes effort, and it is easy to forget to take snapshots or to delete them. If you use a mechanism that automates the snapshot lifecycle, you can run regular snapshot creation and automatic deletion of old snapshots according to rules. In this way, you can keep a set number of backup generations while preventing cost increases from a buildup of unneeded snapshots. If you use the feature that speeds up restoration, you can avoid the initial performance drop when you create a volume from a snapshot. Automating creation, retention, and deletion and putting in place a setup that lets you restore quickly in an emergency lead to stable operations.
Security Considerations When Sharing
When you share snapshots with other accounts, you need to pay attention to security. To share an encrypted snapshot, you also need to allow the other party to use the key that encrypted it, so decide carefully whom you share with. You cannot make an encrypted snapshot public for anyone to access, which prevents unintended leaks of confidential data. When you share, if the other party re-encrypts the snapshot with their own key, you can separate key management. Sharing operations leave a record that you can trace later. Keeping the scope of sharing to a minimum and managing it down to key permissions is the prerequisite for secure sharing.
Integrating Snapshots into a Backup Strategy
It is effective to position EBS snapshots as part of the backup strategy for your whole organization. If you use a mechanism that centralizes backup management, you can manage backups not only of EBS but also of other services with a common policy. Design the frequency of snapshots and the retention period based on targets: how much data loss you can tolerate and how quickly you need to recover. For disaster recovery, replicate snapshots to another region or another account to prepare even for region-wide failures. Backup design that works backward from the targets, rather than case-by-case decisions, supports recovery you can count on.
Summary
EBS encryption and snapshot management form the foundation of data protection and DR. Enforce encryption on all volumes with default encryption and control access with KMS keys. Build a multi-account, multi-region backup strategy through cross-account snapshot sharing and cross-region copy, and reduce long-term storage costs by up to 75% with EBS Snapshot Archive.
References (Official AWS Resources)
The primary sources for this page are the official AWS website and documentation. Check the official pages below for the latest specifications and pricing.
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