https://docs.okd.io/latest/backup_and_restore/application_backup_and_restore/installing/configuring-backup-restore-pvc-datamover.html

The current document on overriding Kopia algorithms is technically accurate but lacks necessary context regarding the OADP Data Mover and fails to highlight a critical configuration warning adequately. Please implement the following changes:

1. Explain the Kopia and Data Mover Relationship (New Section)

Create a new introductory section titled, for example, "Kopia and the OADP Data Mover: A Foundational Relationship." This section must establish why Kopia algorithms are relevant to Data Mover backups.

• Key points to include:

• The built-in Data Mover uses Kopia as its underlying uploader mechanism to move CSI snapshot data to the repository.

• This is true regardless of the uploaderType set for standard File System Backups (FSB). Data Mover always enforces Kopia.

• The environment variables (KOPIA_HASHING_ALGORITHM, etc.) dictate the deduplication, encryption, and chunking behavior for the Data Mover's snapshot movement.

2. Prominent Placement of the Critical Warning

The warning about the configuration being irreversible is crucial.

• Action: Place the following warning in a prominent, dedicated "Warning" or "Important Note" callout box directly before the "Procedure" or DPA YAML example section:

  "The configuration of the Kopia algorithms for splitting, hashing, and encryption in the Data Protection Application (DPA) apply only during the initial Kopia repository creation, and cannot be changed later. To use different Kopia algorithms, configure a new object storage in the Backup Storage Location (BSL) or specify a unique prefix."

3. Detail Algorithm Defaults and Trade-Offs

Enhance the discussion on algorithm selection with concrete data.

• Action: Introduce a table or list that:

• • Explicitly states the default Kopia algorithm for Hashing, Encryption, and Splitter.

• • Provides examples of common override choices (e.g., BLAKE3-256, DYNAMIC-8M-RABINKARP).

• • Offers a brief, helpful summary of the trade-offs (e.g., "BLAKE3-256 is often faster than SHA256" or "Dynamic Splitter impacts deduplication efficiency").

4. Include Troubleshooting Reference

Add a concluding section with the necessary command for gathering diagnostic information for Data Mover issues.

• Action: Include the oc adm must-gather command:
   
   {{oc adm must-gather --image=registry.redhat.io/oadp/oadp-mustgather-rhel<release>:v<version> \
  /usr/bin/gather --skip-tls}}