OSWeekly.com takes a look on the Google File System:

This filesystem actually provides a mountable Linux filesystem and uses our GMail accounts as a storage medium. It is a Python application and uses the FUSE userland framework to provide the filesystem, and uses libgmail library to communicate with GMail. It also supports most of the widely used file operations such as read, write, open, close, stat, symlink, link, unlink, truncate and rename. This implies that we can use all of our favorite UNIX command line tools to operate on files stored in GMail (e.g. cp, ls, mv, rm, ln, grep etc. etc.), though it does not implement a standard API. Files are also organized hierarchically in directories and identified by pathnames. GFS introduces two new operations as well:

- Snapshot

- Record append

According to the authors, snapshot creates a copy of a file or a directory tree at low cost. Record append allows multiple clients to append data to the same file concurrently while guaranteeing the atomicity of each individual client's append. It is useful for implementing multi-way merge results and produce consumer queues that many clients can simultaneously append to without additional locking.

There are few people who think that garbage collection mechanism in C# and Java is wonderful. But what would happen if we extended this garbage collection to our file system? GFS has already accomplished this. Similar to garbage collector of programming languages, GFS does not immediately reclaim the available physical storage.