Most IT admins prefer incremental backups to full ones, as they reduce backup windows, storage costs, and unnecessary redundancy. However, incremental backups can be tricky to manage, particularly as admins look to safely expire snapshots past their retention date.

Since incremental snapshots are incremental relative to previous backups, they form “snapshot chains” that increase in length until the next full backup is taken. As incremental snapshot chains grow, they become slower to recover and costlier to store. With legacy data protection systems, keeping snapshot chains short requires periodic full backups, which are inefficient and costly and can impact SLA compliance. 

Challenges of Shortening Snapshot Chains

With the legacy approach, an incremental snapshot could be past its expiration date but forbidden from expiring if there are newer incrementals in the chain that require it for recovery. When recovering from an incremental snapshot, the recovery aggregates the data of that incremental with all previous incrementals in the chain, plus the first full snapshot, which anchors the chain. As a result, the chain cannot expire until every snapshot in the chain has expired. This method requires chains to grow increasingly long, which in turn enforces higher RTOs and storage costs.

Simplified Archive Management with Rubrik Archive Consolidation

To address these challenges, Rubrik delivers an innovative approach through Archive Consolidation: a method that efficiently deletes expired snapshots by consolidating expired sub-chains into un-expired snapshots. Archive Consolidation reduces chain lengths to enable lower RTOs from archive locations and eliminate periodic full snapshots. Users also benefit from lower storage costs due to shorter, storage-optimized snapshot chains.

How it Works

  1. Configuration: Users must explicitly enable Archive Consolidation on Cloud archive locations. Users must also configure Cloud Compute settings by specifying the VPC, Subnet, and Security Groups where Rubrik Bolt instances can be launched to perform consolidation.
  2. Heuristic check: Rubrik routinely checks archive locations to determine if consolidation is required. The system checks for heuristics such as snapshot chain length, the proportion of the chain that has expired, and the time since the last consolidation. For cloud locations, Rubrik also considers if the storage savings at least offset the cost of the required cloud compute resources.
  3. Consolidation: For on-prem locations, Rubrik reads the expired snapshots from the chain, consolidates their unexpired blocks, and writes the single consolidated snapshot back to the on-prem NFS or object store. For cloud locations, Rubrik spins up a temporary compute instance that reads the expired snapshots, performs the consolidation, and writes back to the chain.

Archive Consolidation is available for S3-compatible object storage, NFS, AWS S3 or S3-IA, and Azure Hot or Cool storage tiers.

To learn more about Rubrik and Archive Consolidation, speak with one of our sales reps.