EnterpriseStrogrageForum.com: Blocks are fundamental, blocks are simple, and blocks haven't changed much since the first disk drive brought storage technology into existence some fifty years ago. The storage industry moves at a whirlwind pace, but underneath all of the virtualization and abstraction, we still work in blocks, writing, reading and keeping track of blocks of data on storage devices across the network.

Block storage has limitations that have become more apparent as demand for scalability and security has grown. With low-level blocks as currency, storage designs require intelligence higher in the stack to manage metadata, to reassemble blocks into the file, or record abstractions understood by applications. Depending on where that intelligence resides, with typical architectures you can choose either scalability (SAN) or sharable data (NAS) — but you can't choose both.

Read more...