# Bucket metadata diagnostics and recovery

`GET /rustfs/admin/v3/export-bucket-metadata` keeps its strict behavior: an unreadable configuration fails the export. The optional `bucket` query selects one bucket; omitting it selects all buckets.

To inspect readable configurations while identifying failures, use the same authenticated endpoint with `?diagnostic=true`. This requires the existing `ExportBucketMetadataAction` permission. A successful response has:

- Filename `bucket-meta-diagnostic.zip` and header `x-rustfs-bucket-metadata-export: diagnostic`.
- Readable entries under `_diagnostic/<bucket>/<config>`; target credentials remain redacted.
- `_diagnostic-manifest.json`, containing `version: 1`, `mode: "diagnostic"`, `complete`, and an `errors` array. Each error identifies `bucket`, `config`, and the fixed code `configuration_unavailable`. The archive excludes unreadable payloads and parser error details.

`complete` reports whether all supported configuration reads succeeded. A diagnostic archive is never a restorable backup, including when `complete` is true. Import rejects the manifest or reserved directory before any bucket creation or configuration write. The reserved directory is not a valid bucket name, so older importers cannot restore diagnostic entries as ordinary bucket configurations.

## Recover unreadable replication targets

RustFS currently accepts the documented `{"targets": [...]}` object format. It cannot decrypt MinIO KMS-encrypted target metadata. Unreadable target payloads remain failures instead of being interpreted as an empty target set; diagnostic export and replacement import do not add MinIO KMS decryption support.

1. Inspect the diagnostic manifest to identify affected buckets. Preserve a separate backup of the original source configuration and any credentials needed for recovery.
2. Prepare a ZIP containing `<bucket>/bucket-targets.json` with a valid RustFS replacement, whose top-level shape is `{"targets": [...]}`. Supply the intended target settings and credentials; exported credentials are redacted. Use `{"targets": []}` only when intentionally clearing all targets, and reconcile any replication rules that reference removed targets.
3. Submit the ZIP to the existing authenticated `PUT /rustfs/admin/v3/import-bucket-metadata` endpoint with `ImportBucketMetadataAction` permission. Import validates the replacement and persists it against the bucket incarnation; it does not need to parse the old target payload successfully.
4. Verify target listing and the intended replication configuration. Retry the ordinary strict metadata export to confirm the unreadable configuration no longer blocks it.

Do not submit the diagnostic archive itself to the import endpoint. Copy only reviewed replacement entries into an ordinary import archive.