Nas Network Attached Storage – File level access to storage using CIFS or NFS
the cost effective option
Storage Area Network SAn Block Level access to storage
you can easily virtualize iSCSI
What is a file storage?
File storage, also called file-level storage, or file-based storage is a type of storage that stores data in a hierarchical structure. The data, which is saved in files and folders, is presented to both the system storing it and the system retrieving it in the same way.
What is a block of data?
At the finest level of granularity, Oracle stores data in data blocks (also called logical blocks, Oracle blocks, or pages). One data block corresponds to a specific number of bytes of physical database space on disk. The next level of logical database space is an extent.
What is a block device?
Block devices are disk devices for which the kernel provides caching. This caching makes block-devices almost unusable, or at least dangerously unreliable. The caching will reorder the sequence of write operations, depriving the application of the ability to know the exact disk contents at any one instant in time.