Today, storage is the most discussed topic within IT.
Simply put, storage is the repository of the information that is the lifeblood of every business. In many ways, information today is the business. It is the products we sell and buy; it is the supply chain that results in our products and services; it is the orders we place; it is the invoice raised; it is the payments we make; it is the market intelligence we rely on to make decisions; it is the knowledge about each customer that we use to improve retention and loyalty; it is the partnerships and alliances we make; it is our vision, our strategy and our planning horizons. Information truly is the business.
It is both the criticality of information and the increasing proliferation of information that has caused such an intense scrutiny of storage.
Until the events of Sept. 11, storage was on track to grow at around 100 percent per year. Put that in perspective: a user with 1 terabyte of storage today, growing at 100 percent compound annual growth rate, would have some 32 terabytes to deal with 5 years from now. The typical reaction of most CIOs is: how on earth am I going to manage that amount of data with the people I have now, and how am I going to pay for it?
While the current growth has slowed to approximately 60 percent, there is considerable opinion growing that the historical 100 percent rates will return in 2002.
During the past two or three years, two technologies have emerged as significant changes in storage--storage networking and storage virtualization. In addition, two more have recently begun to stimulate discussion--IP storage and storage management software.
Storage networking will gradually, some say rapidly, change the architectural landscape for how storage is accessed by applications. There are two techniques for implementing storage networks--Network Attached Storage (NAS) and Storage Area Networks (SANs).
The majority of storage today is still dedicated to just one server. This is called Direct Attached Storage (DAS). The problem with DAS is that it is only accessible by one server, and can only grow as much as that server is able to support. This ability to grow is called "scalability". In addition, storage is typically inefficiently used. Either the server has plenty of capacity available, which is wasteful, or it doesn't have enough, so placing the applications at risk of running out of capacity. Finally, when storage changes in a DAS environment, typically the applications must be stopped and the server rebooted to recognize the changes.
The purpose of storage networks, whether they are the NAS variety or the SAN variety, is to improve availability, to introduce economies of scale by sharing storage across multiple servers, and to improve scalability.
NAS is a specialized server that is optimized for file storing and sharing and retrieving data. The NAS server is attached to the same LAN as servers and PC clients, and performs file-level data requests from other servers on the LAN. NAS implementations are usually easy to install because the NAS server owns all the storage resources it needs. Networked attached storage implementations usually consist of the server, its operating system and the disk it needs to store the data.
A SAN consists of storage applications, storage devices--both RAID arrays and tape--attached to a network that is separate from the LAN. LANs are typically Ethernet networks as opposed to SANs which are typically based on Fiber Channel technology. Unlike NAS systems which deal with data at the file level, SANs operate at the block level, which is typical of large data operations such as database applications.
In the next column, we will discuss the role of virtualization in the context of storage networks.
Rob Nieboer is a corporate evangelist for StorageTek and is currently responsible for global industry analyst relations for the company. Nieboer is a frequent speaker at StorageTek and industry events around the world. Rob's background includes some 34 years as an IT practitioner, with the last 17 years focused on storage. He has a particular interest in management issues surrounding storage and in storage virtualization.