thanos-io/thanos · error

upload to backup

Error message

upload to backup

What it means

backupDownloaded uploads the on-disk TSDB block to the backup bucket with block.Upload; any failure is wrapped as "upload to backup". This means the local block was considered valid but the multi-file upload to the backup bucket failed partway.

Solutions

1. Verify backup bucket credentials and write permissions
2. Check object store limits (max object size, multipart config) and network connectivity
3. Retry the repair; re-upload is safe when the destination is absent
4. Inspect the wrapped block.Upload error for the specific object and cause

// pre-check backup bucket write access
err := backupBkt.Upload(ctx, "__perm_test__", strings.NewReader(""))

err := backupDownloaded(ctx, logger, bdir, backupBkt, id)
if err != nil && strings.Contains(err.Error(), "upload to backup") {
	// retry with backoff; ensure destination dir absent to avoid conflict
}

When it happens

Trigger: BackupAndDelete/BackupAndDeleteDownloaded -> backupDownloaded -> block.Upload(ctx, logger, backupBkt, bdir, metadata.NoneFunc) fails (bucket permissions, size limits, network errors, partial upload).

Common situations: Backup bucket credentials missing write permission; object store rejecting large files; network interruption during multipart upload; misconfigured backup bucket name/endpoint.

Understand the failure class

Background: "API request failed": what wrapped HTTP errors from external APIs mean and how to find the real cause — this error's family across 29 libraries.

Related errors

• upload downsampled block
• upload file to bucket
• upload of failed
• upload to target bucket
• upload

AI-assisted analysis of thanos-io/thanos@35b8b99117 (2026-09-07). Data as JSON: /api/errors/6251a883a490bcff. Report an issue: GitHub.

Appendix: source

Thrown at pkg/verifier/safe_delete.go:142

	return nil
}

// backupDownloaded is a helper function that uploads a TSDB block
// found on disk to the given bucket. An error is returned if any operation
// fails.
func backupDownloaded(ctx context.Context, logger log.Logger, bdir string, backupBkt objstore.Bucket, id ulid.ULID) error {
	// Safety checks.
	if _, err := os.Stat(filepath.Join(bdir, "meta.json")); err != nil {
		// If there is any error stat'ing meta.json inside the TSDB block
		// then declare the existing block as bad and refuse to upload it.
		// TODO: Make this check more robust.
		return errors.Wrap(err, "existing tsdb block is invalid")
	}

	// Upload the on disk TSDB block.
	level.Info(logger).Log("msg", "Uploading block to backup bucket", "id", id.String())
	if err := block.Upload(ctx, logger, backupBkt, bdir, metadata.NoneFunc); err != nil {
		return errors.Wrap(err, "upload to backup")
	}

	return nil
}

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