hyperledger/fabric · error

error while closing the snapshot file: %s

Error message

error while closing the snapshot file: %s

What it means

Done calls c.file.Sync() to force written data to stable storage; if the OS-level sync fails, the raw error is returned (no wrap). A failure here means data may not be durably persisted and the snapshot cannot be trusted as complete. The hash is not returned because the file finalization did not succeed.

Source

Thrown at common/ledger/snapshot/file.go:108

// EncodeUVarint encodes and appends a number to the data stream
func (c *FileWriter) EncodeUVarint(u uint64) error {
	n := binary.PutUvarint(c.varintReusableBuf, u)
	if _, err := c.multiWriter.Write(c.varintReusableBuf[:n]); err != nil {
		return errors.Wrapf(err, "error while writing data to the snapshot file: %s", c.file.Name())
	}
	return nil
}

// Done closes the snapshot file and returns the final hash of the data stream
func (c *FileWriter) Done() ([]byte, error) {
	if err := c.bufWriter.Flush(); err != nil {
		return nil, errors.Wrapf(err, "error while flushing to the snapshot file: %s ", c.file.Name())
	}
	if err := c.file.Sync(); err != nil {
		return nil, err
	}
	if err := c.file.Close(); err != nil {
		return nil, errors.Wrapf(err, "error while closing the snapshot file: %s ", c.file.Name())
	}
	return c.hasher.Sum(nil), nil
}

// Close closes the underlying file, if not already done. A consumer can invoke this function if the consumer
// encountered some error and simply wants to abandon the snapshot file creation (typically, intended to be used in a defer statement)
func (c *FileWriter) Close() error {
	if c == nil {
		return nil
	}
	return errors.Wrapf(c.file.Close(), "error while closing the snapshot file: %s", c.file.Name())
}

// FileReader reads from a ledger snapshot file. This is expected to be used for loading the ledger snapshot data
// during bootstrapping a channel from snapshot. The data should be read, using the functions `DecodeXXX`,
// in the same sequence in which the data was written by the functions `EncodeXXX` in the `FileCreator`.
// Note that the FileReader does not verify the hash of stream and it is expected that the hash has been verified
// by the consumer. Later, if we decide to perform this, on-the-side, while loading the snapshot data, the FileRedear,

View on GitHub (pinned to 2736b63f8f)

Solutions

  1. Inspect the raw OS error returned by Sync
  2. Avoid snapshot output on network filesystems with unreliable fsync; write to local disk
  3. Retry the export and verify the resulting snapshot hash
Defensive patterns

Strategy: retry

Validate before calling

if err := syscall.Access(snapshotDir, os.O_RDWR); err != nil { return errors.New("snapshot dir not writable") }

Try / catch

hash, err := w.Done()
if err != nil {
    log.Errorf("sync/close failed for snapshot %s: %v", path, err)
    w.Close(); return err // retry the whole export
}

Prevention

When it happens

Trigger: c.file.Sync() returns an error during Done (after a successful Flush).

Common situations: ENOSPC/EIO on the underlying storage, NFS/network filesystems that don't support fsync properly, or container storage drivers rejecting fsync.

Related errors

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/9837f107d51c4540. Report an issue: GitHub.