Storage software is steadily growing in importance, but hardware still underpins storage. Storage used to come parcelled in with the servers, but a growing proportion of new storage is DAS and SAN attached. Storage hardware can still be considered as a pyramid, but the pyramid is now differentiated by availability, as well as performance. The levels of the pyramid are defined by the requirements of the content of the data stored there. Content management overlaps into the information lifecycle management area, but in simplistic terms, content can be defined by
- Structured Content
- Databases which need high availability and performance
- Semi-Structured content
- Text files which need good availability and performance
- Unstructured content
- Bitmaps, pictures and videostreams which may just require acceptable availability and performance
These definitions will vary according to the value your industry puts on each type of content. On top of this, the value, and service requirements of data change with time, so an older document can be placed into deep archive, while a new document needs to be on fast access disk, as it will probably be accessed frequently.
The hardware point behind this, is that your storage infrastructure should be able to store data at its correct level, depending on its current needs. Data at the top of the pyramid gets the best performance and availability, but is expensive to store, while data at the bottom if the pyramid is cheapest, but gets slower access and poorer availability. Get the balance right, and you get a cost effective storage infrastructure which meets your customers needs.
This section discusses storage hardware, both disk technology, and tape technology, including virtual tape.
The pyramid above does not show the way all the storage devices are connected together. This is discussed in the Storage Area Network section.