# Google File System

## Requirements in GFS

* Big
* Fast
* Sharding
* Automatic recovery
* Single Data center
* Internal use
* big sequential reads and writes

## Architecture

100s of clients 1 Master Chunk Servers (CS) each with one or two disks The naster knows where the chunks are the master keeps a list of files and their chunk information

## Master Data

Two main tables that are important. One maps filenames to array of chunk handles another maps chunk handles to a list of chunk servers, version #, primary chunk, lease expiration A log and checkpoint on disk