# Eventual consistency for deleted items and renames

Object storage environments can contain billions of objects, making traditional methods of tracking changes (such as directory-based scans) expensive in terms of memory, disk space, and processing time.

To improve scalability, the backup process uses an eventual consistency approach. Instead of tracking every deletion and rename during each backup scan, these operations are deferred and processed separately. This significantly reduces resource consumption while maintaining data consistency over time.

## How it works

A consistent backup job is responsible for reconciling the backup with the current state of the object storage. By default, this job runs every 15 days. Regular backup jobs continue to capture new and modified objects between consistent backup runs.

After a consistent backup, Commvault:

- Asynchronously identifies objects that have been deleted and detects renamed objects.

- Records the identified deletions and renames information for processing during a subsequent incremental backup.

- Once the asynchronous process completes, consistency is achieved by the first incremental backup that runs after the process has finished.

## Configuration

For most environments, keep the default consistency behavior and run regular backup jobs between consistent backup runs.

- Keep the default schedule unless you need faster reconciliation for deleted and renamed objects. To change how often consistent backup jobs run, configure the nBackupConsistencyInterval additional setting.

- Set the bMakeBackupConsistent additional setting to true when you want the next incremental backup to run as a consistent backup. After the consistent backup completes, set `bMakeBackupConsistent` back to false. If this setting remains enabled, all subsequent incremental backups run as consistent backups, which can add unnecessary overhead when continuous consistency checks are not required.

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