# Migrate Backblaze B2 S3 bucket: Tenant-scoped object prefixes

Move object storage from Backblaze B2 S3 bucket to Ample, one component at a time. Destination verified on Ample: every tenant's objects stored under **tenants//** in a private bucket with an ownership row per object, reads refused for keys outside the caller's prefix or not owned (cross=forbidden), and a prefix-bound listing returning only that tenant's objects (own=1).

## Source procedure:
- Inventory the bucket with `rclone size` or the B2 dashboard.
- Not migrated automatically: B2 file versions, lifecycle rules and application-key restrictions are not migrated.

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

## Rollback:
Keep the source untouched until you confirm; nothing at the source is changed or deleted by this guide.

## Workflow Steps
1. **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.

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

3. **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).

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

5. **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.
   - Command: `ample bucket create --name `

6. **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/tenant-scoped-object-prefixes`).

7. **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.

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

## Limitations
- Documentation only: nothing is executed automatically and no execution binding is offered.
- The source-side procedure is documented from Backblaze B2 S3 bucket's standard tooling and was not executed in this catalog's evidence; the destination side was verified with the pattern fixture.
- No full source-product parity is claimed: B2 file versions, lifecycle rules and application-key restrictions are not migrated.
- Verified on the node-22 template at s-1vcpu-1gb; region, compliance and request-duration limits are unknown.

## Cost Estimate
- **Currency:** USD
- **Monthly Amount:** $5.00
- Basis: size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty.
- **Components:**
  - **App server:** size s-1vcpu-1gb, quantity 1.0, monthly amount $5.00.

## Evidence Summary
- **Kind:** canary_run
- **Summary:** Destination side verified: the Express pattern fixture deployed on Ample and its checks passed. The source-side export from Backblaze B2 S3 bucket is documented from the vendor's standard tooling and was not executed by this catalog's evidence.
- **Observed At:** 2026-09-21T02:34:39Z
- **Implementation Revision:** 1d28ae0-dirty (CLI 0.1.21)
- **Expires At:** 2027-03-20T02:34:39Z

## Next Actions
- Browse the catalog index
- Search published recipes by intent, stack and constraints
- Prepare a side-effect-free deployment plan for an authorized project
- Read the existing agent authentication setup
- Browse Backblaze B2 S3 bucket
- Browse Tenant-scoped object prefixes
- Browse Migrate objects