remember my post
this article is about the technology behind that!!!
The btrfs file system is designed to meet the expanding scalability requirements of large storage subsystems. As the btrfs file system uses B-trees in its implementation, its name derives from the name of those data structures, although it is not a true acronym. A B-tree is a tree-like data structure that enables file systems and databases to efficiently access and update large blocks of data no matter how large the tree grows.The btrfs file system provides the following important features:
• Copy-on-write functionality allows you to create both readable and writable snapshots, and to roll back a file system to a previous state, even after you have converted it from an ext3 or ext4 file system.
• Checksum functionality ensures data integrity.
• Transparent compression saves disk space.
• Transparent defragmentation improves performance.
• Integrated logical volume management allows you to implement RAID 0, RAID 1, or RAID 10 configurations, and to dynamically add and remove storage capacity.
You can find more information here :- http://btrfs.wiki.kernel.org
Below is some real time requirement , we can understand the need of such technology
According to http://blog.contractoracle.com/
I recently had a customer who wanted to reduce storage costs. They had a 13TB PROD database, and needed 40 copies of the database to support DEV and TEST activities, totalling over 500TB.