benbjohnson/litestream · error

write page to buffer: %w

Error message

write page to buffer: %w

What it means

VFSFile.writeToBuffer's WriteAt of a dirty page into the durability buffer file failed. The buffer file (buffer_path) is unwritable or the disk is full — dirty pages can no longer be staged safely before replication.

Source

Thrown at vfs.go:2224

// writeToBuffer writes a dirty page to the write buffer for durability.
// If the page already exists in the buffer, it overwrites at the same offset.
// Otherwise, it appends to the end of the file.
// Must be called with f.mu held.
func (f *VFSFile) writeToBuffer(pgno uint32, data []byte) error {
	var writeOffset int64
	if existingOff, ok := f.dirty[pgno]; ok {
		// Page already exists - overwrite at same offset
		writeOffset = existingOff
	} else {
		// New page - append to end of file
		writeOffset = f.bufferNextOff
		f.bufferNextOff += int64(len(data))
	}

	// Write page data (no header, just raw page data)
	if _, err := f.bufferFile.WriteAt(data, writeOffset); err != nil {
		return fmt.Errorf("write page to buffer: %w", err)
	}

	// Update dirty map with offset
	f.dirty[pgno] = writeOffset

	return nil
}

// clearWriteBuffer clears and resets the write buffer after successful sync.
func (f *VFSFile) clearWriteBuffer() error {
	// Truncate file to zero
	if err := f.bufferFile.Truncate(0); err != nil {
		return fmt.Errorf("truncate buffer: %w", err)
	}

	// Reset next write offset
	f.bufferNextOff = 0

View on GitHub (pinned to 4ed7a308f6)

Solutions

1. Check disk space and permissions on the buffer file path
2. Verify buffer_path points to writable storage

When it happens

Trigger: Thrown at vfs.go:2224 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of benbjohnson/litestream@4ed7a308f6 (2026-09-06). Data as JSON: /api/errors/65c63f5f5661a382. Report an issue: GitHub.