hyperledger/fabric · error

error while renaming dir [%s] to [%s]:

Error message

error while renaming dir [%s] to [%s]:

What it means

generateSnapshot finalizes a snapshot by atomically renaming the temp directory to its final location <snapshotsRootDir>/<ledgerID>/snapshots/<blockNum>. This error wraps os.Rename failure, meaning the snapshot was generated but could not be moved into place and the temp dir is removed (snapshot is NOT produced).

Source

Thrown at core/ledger/kvledger/snapshot.go:151

		configsHistoryExportSummary, stateDBExportSummary,
	); err != nil {
		return err
	}
	logger.Debugw("Generated metadata files", "channelID", l.ledgerID)

	if err := fileutil.SyncDir(snapshotTempDir); err != nil {
		return err
	}
	slgr := SnapshotsDirForLedger(snapshotsRootDir, l.ledgerID)
	if err := os.MkdirAll(slgr, 0o755); err != nil {
		return errors.Wrapf(err, "error while creating final dir for snapshot:%s", slgr)
	}
	if err := fileutil.SyncParentDir(slgr); err != nil {
		return err
	}
	slgrht := SnapshotDirForLedgerBlockNum(snapshotsRootDir, l.ledgerID, lastBlockNum)
	if err := os.Rename(snapshotTempDir, slgrht); err != nil {
		return errors.Wrapf(err, "error while renaming dir [%s] to [%s]:", snapshotTempDir, slgrht)
	}
	return fileutil.SyncParentDir(slgrht)
}

func (l *kvLedger) generateSnapshotMetadataFiles(
	dir string,
	txIDsExportSummary,
	configsHistoryExportSummary,
	stateDBExportSummary map[string][]byte,
) error {
	// generate metadata file
	filesAndHashes := map[string]string{}
	for fileName, hashsum := range txIDsExportSummary {
		filesAndHashes[fileName] = hex.EncodeToString(hashsum)
	}
	for fileName, hashsum := range configsHistoryExportSummary {
		filesAndHashes[fileName] = hex.EncodeToString(hashsum)
	}

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Check if a snapshot for that block number already exists at snapshots/<ledgerID>/snapshots/<blockNum> — if so, the snapshot already exists; nothing to do
2. Ensure temp and final directories live on the same filesystem/volume
3. Avoid concurrent snapshot generation or external cleanup touching the snapshots dir
4. Re-run GenerateSnapshot() after resolving; stale temp dirs are cleaned up automatically

Example fix

// before (risky)
snapshots:
  rootDir: /mnt/nfs/snapshots  # temp subdir on same NFS but different export
// after
snapshots:
  rootDir: /var/hyperledger/production/snapshots  # single local filesystem

finalDir := filepath.Join(snapshotsRootDir, ledgerID, "snapshots", fmt.Sprintf("%d", lastBlockNum))
if _, err := os.Stat(finalDir); err == nil {
    return fmt.Errorf("snapshot for block %d already exists at %s", lastBlockNum, finalDir)
}
tmpDev, _ := getDev(snapshotsRootDir); finDev, _ := getDev(filepath.Dir(finalDir))
if tmpDev != finDev { return errors.New("temp and final snapshot dirs must be on the same filesystem") }

err := ledger.GenerateSnapshot()
var le *os.LinkError
if errors.As(err, &le) && errors.Is(le.Err, syscall.ENOTEMPTY) || errors.Is(le.Err, syscall.EEXIST) {
    log.Info("snapshot already exists for this height; skipping")
    return nil
}

When it happens

Trigger: os.Rename(snapshotTempDir, finalDir) fails: final dir already exists (snapshot for that block number already taken), temp dir removed by concurrent process, or cross-device rename if temp dir is on a different filesystem than the final dir.

Common situations: Re-running GenerateSnapshot() for a block height that already has a snapshot; snapshots root on NFS/bind-mount layouts where temp and final paths span devices; cleanup jobs deleting temp dirs mid-generation.

Related errors

• error while reading bootstrappingSnapshotInfo file
• failed to read bootstrappingSnapshotInfo file under blocksto
• error renaming temp file '%s'
• error while deleting the dir: %s
• error while creating the dir: %s, ensure peer has write acce

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/b189a0309e9d7ee2. Report an issue: GitHub.