SANs provide succor to storage infostructure

We all are aware that enterprises, be it the click and mortar or the brick and mortar (the classic case of merger of Time Warner and AOL), and with the mega mergers and acquisitions happening around the globe, all of them thrive on robust storage technologies and strong back-up. For a pure e-biz player, say Fabmart, managing the show entirely of storing, retrieving and protecting the data, and most importantly ensuring online accessibility can be tedious if not unachievable.

This is where SANs can help in e-business - they provide the infrastructure to change storage from a mere static and laborious task into a strategic factor in managing the e-business aspect. But, how does all this happen? For that we need to understand the principles of networks and extend the concepts to storage also and assembling them with switches, routers/hubs to bridge the various LANs and WANs.

Says Satyan Gopalan, National Manager, Storage solutions, Computer Associates(CA), " The advantage with the SANs is that you no longer have to take systems offline to add storage or reconfigure the systems. SANs help in building scalable, high-availability storage networks with limited resources. It improves performance as it reduces and moves the load on servers to separate networks."

E-Business and Information Intensity

According to a white paper on SAN and e-business, companies can be categorized based on their level of "information intensity." For instance, hotels and fast-food restaurants commonly referred to as "hug and lug" cos., belong to the first category. Well, how often would one place a lunch or snacks order online? If the Web site goes down, the overall business won''t be significantly impacted. No Web, no problem.

The second category "clicks and mortar" refers to companies using a hybrid model, such as Dell or Barnes & Noble.com-who do both offline and online commerce, and still have warehouses, shipping, and all the physical aspects of running a business. When their Web sites go down, their businesses are impacted, but they don''t completely shut down. No Web, no advantage.

The third category includes "online businesses," such as Amazon.com, which, without data about their customers, are dead in the water. No Web, no revenue.

The fourth category consists of pure "information aggregators," such as eBay and Yahoo!. These are the true e-business companies-when their Web sites go down, their businesses come to a halt. No Web, no company. And precisely for these companies, SANs can be a critical tool for them as they move to greater levels of information intensity. SANs provide the ability to build completely redundant and reliable storage networks that match messaging and telecom networks.

How Are SANs Significant?

SANs provide the tools to manage more customers, partners, suppliers, employees, and transactions within the existing enterprise. With greater access to storage resources, the risk also of exposing security breaches also increases. However, SANs provide an added level of security and security management tools, which are critical in the e-business world. Says, EMC Country Manager, T. Srinivasan, " SANs provide higher availability through ready access to data, greater scalability by mirroring the data across multiple channels, and providing Cascadability to all data across the enterprise. This apart, SRDF( Symmetrix Remote Data Finder), providers another important security feature of disaster recovery in case of data loss".

SANs and Backup

Well as discussed before of the criticality of back-ups, let's analyze those process and find how they reduce the resources required and provide tremendous support. According to experts, a typical network backup requires ten copies of the data; a LAN-free backup needs five, and a serverless backup requires one copy of the data. However, with the network, one would be creating anywhere between 10 to 40 copies, depending on the operating system. This creates considerable CPU overhead, and the additional processing power means one can''t do any parallel process while it''s backing up. But as Satyan said before, SANs takes care of off-loading the overheads on CPU and servers.. Some of the various ways of back-ups are: (We have discussed SAN topologies in our previous features)

LAN-free Backup

In this scenario, the data commands are moved across the typical messaging network, but the data is transferred across the backend SAN. This provides significant upside in performance and reduces network traffic dramatically. Although it doesn''t really help the CPU overhead, it can reduce backup time by more than 50 percent.

Serverless Backup

The next step in storage technology evolution is serverless backup, where the disk array systems talk to the tape libraries and can move backup data, in one copy, directly from one SCSI command set to the other, using Fiber Channel as the connectivity layer. This provides the benefits of LAN-free backup with the added benefit of reducing the CPU overhead. Serverless backup can reduce backup windows from hours to minutes.

Intelligent SAN Systems

Just as the networking world evolved from hubs to intelligent switches, storage networks require intelligent subsystems that can manage in a high-performance, networked environment. With multiple servers accessing multiple devices, the need for switching, arbitration, and management is all the more high now. Intelligent storage subsystems can manage themselves, communicate with servers, and manage interactions with other storage subsystems-a critical attribute of a good SAN system.

Concurs Apara Enterprise solutions, Country Manager, Binod Kumar Panda, "SANs improves network and server performance in several ways and one of them is to offload from servers of storage management tasks of back-ups and file sharing and it centralizes storage management process".

Other benefits include:

• Direct access to the storage shared by multiple servers
• Reduced network traffic on the front-end network
• Reuse of previous investments in storage in the SAN environment
• Elimination of SCSI limitations
• Redundancy

We now have a fair idea of how SANs have complemented the requirements of e-business of enhancing the 365 days and 24/7 availability feature and have become a critical part of the infostructure, just as servers, routers, and high-end RAID systems are today. This allows a company to focus on its core business, rather than on the technology, which is only a means to do business. It was not that DAS (Direct Attached Storage) or NAS (Network Attached Storage) did not serve the purpose but each of them had their inherent disadvantages ranging from incompatibility with various devices to non-centralizing storage processes to heavy load on the network.