Tuesday, September 15, 2009

Five Reasons why SAN and NAS may not meet the needs of SMB's.

In an earlier post I talked about the seven key attributes of SMB storage but what I did not talk about was the storage options available to the SMB.

There are three traditional architectures; DAS, SAN, and NAS. Direct Attached Storage (DAS) with its purchasing simplicity still dominates but as the volume of data and the number of users grow, Network Attached storage (NAS) and Storage area Networks (SAN) continue to make inroads into the SMB IT space. The improved storage, operational economics of SAN and NAS is what is stimulating the increased market share of these options with NAS and its simpler user experience evolving as the more popular. Unfortunately the realities of unpredictable but dynamic growth are beginning to compromise their benefits. However there is another emerging technology that is establishing credentials in the commercial space, clustered storage architectures, but that is the subject of another blog.

The object of this blog is to briefly comment on the traditional storage architecture, one normally referred to as monolithic and is an architecture that is independent of whether the storage is being implemented as a SAN or NAS. A monolithic architecture or in today’s topical parlance, scale-up, is an architecture that is characterized by storage that sits behind dedicated controllers or server heads. It is an architecture that dates back into the 1950’s when direct attached, on-line storage was in the nascent stages and over the years evolved to be the dominant storage architecture in today’s data center. This architecture has been very successful as the product lines of IBM, EMC, HDS, HP and the tier two folks such as 3PAR, Nexsan, Compellent, DDN and BlueArc will testify.

However despite its many attributes of a monolithic architecture it has five distinct disadvantages that creates significant angst for the SMB;

1. Tends to create inefficient “Islands of Storage” that increase cost and management complexity.
2. Creates bottlenecks that can challenge data access.
3. Storage is generally poorly utilized driving up the cost of usable storage.
4. Tends to be complex and have limited flexibility and disruptive scalability that drives defensive “poor” purchasing behavior.
5. Have inherent single points of failure that challenge reliability and data access.

These failings tend to drive complexity and cost which encourages poor purchasing behavior. It is not uncommon to witness storage administrator’s purchase more storage than is immediately required to avoid the significant hassle and risk associated with growth. Advanced purchasing while appreciated by vendors is the wrong way to purchase storage. If risk can be eliminated why pay today’s prices for tomorrow’s requirement incurring not only increasing capital cost but additional operational cost such as energy and cooling. While these are all characteristics that work against the storage consumer by introducing cost, complexity, and as noted, angst into the routine tasks of managing storage and surviving data growth there is a technology that promises a more effective approach.

Clustered storage appears to offer an interesting set of alternative attributes that directly address the failings of monolithic options and as noted earlier will be the subject of a future post.