# Migrate Backblaze B2 S3 bucket: Private document library

Move object storage from Backblaze B2 S3 bucket to Ample, one component at a time. Destination verified on Ample: a role-to-document access model with negative tests (401 without identity, 403 for the wrong role) and a private-bucket round-trip for the allowed role (private=ok).

## Procedure

### Inventory the source
- List what Backblaze B2 S3 bucket provides beyond the component you are moving. Out of scope here: B2 file versions, lifecycle rules and application-key restrictions are not migrated.

### Source step 1
- Inventory the bucket with `rclone size` or the B2 dashboard.

### Source step 2
- Copy objects with `rclone sync` from the B2 S3-compatible endpoint to the Ample bucket endpoint using the issued credentials (path-style).

### Source step 3
- Verify a sample of objects by size and checksum after the copy.

### Create the destination bucket and copy
- Create the bucket, copy with rclone or the S3 CLI in path-style mode using the issued credentials, then pass the credentials to the app as encrypted S3_* variables.

```bash
ample bucket create --name <bucket-name>
```

### Validate before cutover
- Run the app's own checks and, for data, compare counts and checksums; the example checks are the pattern self-tests (/p/private-document-library).

### Cut over
- Switch the app's S3_* environment to the Ample bucket with a redeploy, verify reads and writes, keep B2 read-only until confirmed.

### Rollback
- Point DNS or configuration back to the source. The source was never modified; deletion is a separate, user-executed step after validation.

## Workload
- Private document library

## Migration Source
- Backblaze B2 S3 bucket

## Prerequisites
- Authorized access to the Backblaze B2 S3 bucket source and its export tooling
- An inventory of every component in scope and out of scope
- A validated backup or copy before any cutover
- An Ample account token with servers:write, buckets:write

## Limitations
- Documentation only: nothing is executed automatically and no execution binding is offered.
- No full source-product parity is claimed: B2 file versions, lifecycle rules and application-key restrictions are not migrated.

## Cost Estimate
- **Currency**: USD
- **Monthly Amount**: 5.0
- **Note**: Destination always-on monthly price of the tested sizes; apps auto-pause when idle. Source costs are unknown to Ample.

## Evidence Summary
- Destination side verified: the Express pattern fixture deployed on Ample and its checks passed.

## Next Actions
1. **[Browse the catalog index](api/catalog_index)**
2. **[Search published recipes by intent, stack and constraints](api/catalog/search)**
3. **[Prepare a side-effect-free deployment plan for an authorized project](api/catalog/plan)**

## Success Checks
- Destination app responds on its public URL.
- Private-document-library check from the destination example.
- Data or object counts and checksums match the source.