The Synchronous Write Problem
Stateless NFS servers must commit each operation to stable storage before responding to the client.
- Interferes with FS optimizations, e.g., clustering, LFS, and disk write ordering (seek scheduling).
Damages bandwidth and scalability.
- Imposes disk access latency for each request.
Not so bad for a logged write; much worse for a complex operation like an FFS file write.
The synchronous update problem occurs for any storage service with reliable update (commit).