Is there any abstraction layer to work with GFS or HDFS?

Question

The SQL and NOSQL databases are used by facebook

1.Whether it uses GFS or HDFS or BOTH or some other?

2.What are the different Abstraction application layer available to work on HDFS AND GFS ??

3.I heard about HADOOP , How Map Reduce works ?

kindly narrate the advantages.

And also narrate about the second question deeply.

Answer 1

1. This is not a real question.
2. There are really thousands of articles out there.
3. To guide you into the right direction:

Facebook uses a lot of different technologies. SQL and NoSql. It is known that they use a lot Cassandra. Have a look at this video from the director of engineering from Facebook.

Here are also some more links of the Facebook architecture: Facebook Architecture