What are the functionalities of Distributed File systems and Distributed Storage Systems?

Question

i'm reading cloud vendors solutions for the distributed storage systems such as Amazon Dynamo and Google Big Table.

and really confused in two terms :

1. what is Distrubuted file systems, Do cloud vendors use different kinds of DFS ?
2. what is Distributed storage systems for?
3. what are differences of these terms and functionalities ?

if i understand these terms i will create the general architecture of the cloud vendors, any good tutorial or web page will be appreciated.

Thanks

Answer 1

1. DFS is a very generic term for a system that makes files available from multiple physical locations. This can be redundant copies (for performance or redundancy); or it can be a single logical file system with individual files placed on different physical servers.

2. Distributed Storage is abstracting the physical storage through a single logical presentation; basically you have storage in multiple locations (different servers or dedicated hardware), which looks to the application as though it's a single storage system.

3. To an extent, they're being used as marketing buzz-words. They will mean nothing unless you know exactly how they're implemented, and thus how to take advantage of them.

The Wikipedia articles have a more in-depth explanations for Distributed File Systems and Storage Virtualization (which includes physically diverse storage).