Will Network Attached Storage Change the Way That You Do Business?

By Page Tagizad

 

Not long ago, networking consisted simply of connecting shared peripheral devices (storage systems, printers, etc.) to general-purpose file servers. Users accessed data/applications indirectly through the file server. Although it seemed revolutionary at the time, the process of circuitous data access created an I/O burden on the server, causing degraded performance and significant wait times.
 
Today's IT Manager must have systems in place to meet the current demands for immediate access to electronic files, including e-mail and Internet/Web resources. Typically, servers devote over half their processing power to handling storage features. When the traditional server-centric network configuration cannot efficiently meet a company's evolving storage needs, a data-centric model must be implemented: intelligent stand-alone Network Attached Storage (NAS) devices.
 
In addition to efficiency, data-centric systems offer more reliability, flexibility and scalability, plus a lower cost of administration than the server-centric arrangements of the past. Before purchasing a new shared storage system, however, there are several key issues to consider; the purpose of this article is to examine the features and benefits of today's data-centric NAS devices.
 
Server-Centrism vs. Data-Centrism
 
If data and resources are routed through the file server, as in a LAN or WAN configuration, users often face significant lag times. To compensate, expensive hardware upgrades like faster CPUs and increased memory are often seen as a necessary evil.
 
When intelligent stand-alone devices are connected directly to the network, and storage functions are moved off the server onto NAS devices, servers perform inordinately faster. Workstations retrieve data immediately from the NAS device, resulting in significantly faster response times.
 
Despite increased performance, interoperability, ease of administration, and fault tolerance, there are inherent challenges unique to NAS systems and their implementation. Products and vendors differ greatly, as do features and benefits.
 
Cross-Platform Compatibility
 
Most large companies find it necessary and practical to incorporate a number of operating systems/protocols for their different workstations. Today it is common to find IBM-compatible computers in place in one department, Apple Macintosh systems across the hall, and UNIX workstations downstairs. Such heterogeneity increases the storage burden on general-purpose file servers.
 
In a server-centric configuration, users may only access data through servers with compatible protocols. Redundant duplication of applications and files for each platform wastes storage space, and opens the door for inconsistencies when a variety of users are modifying the same files.
 
The NAS device must support cross-platform users and allow for interoperability without purchasing additional software or hardware. It must support users on DOS, Windows 95, Windows NT, UNIX® and Mac platforms, and can be accessed by Ethernet, Token Ring, FDDI and ATM network cards. An NAS device must also afford interoperability with a variety of networking communications protocols like NFS, NetWare, LAN Manager, and AppleShare.
 
Throughput and I/O Load
 
File servers generally forgo performance to support general functions, and experience degraded performance when responding to bulk I/O requests. With NAS devices, throughput is sufficient to satisfy as many users as needed with minimum lag time.
 
When data-centric NAS is in place, the server is left to manage applications and not I/O, providing better overall performance and increasing the server's lifespan greatly. In the case of bulk data that is sent directly to the user without processing by an application, such as video-on-demand, databases, and graphics, the server is bypassed entirely.
 
Scalability
 
The corporate environment relies on word processing, finance and accounting programs, presentation and graphics capabilities, and database applications, among others. As technology adapts to need, more and more non-traditional data must be accommodated, and it is common to find inline video, audio, rich text and HTML formats in use in many companies. The enormous amount of data, which expands as a company prospers, demands sufficient disk space for the growing enterprise.
 
When opting for an NAS solution, scalability is a critical feature. Storage needs can easily be expected to scale in line with other adjuncts to the network like disks and users, or any time resources are added to enhance the system. The NAS appliance must be a scalable, flexible product that offers a RAID architecture for optimum economy and practicality, and can be used in cluster configurations along with other NAS appliances for still more capabilities.
 
Installation/Administration
 
NAS devices are usually designed for fast and easy network connection, with no impact on the network itself or its users. Regardless of the ease of installation, a vendor should thoroughly back its product with 24/7 technical support.
 
System administration can vary greatly from one NAS device to another. For the greatest benefit, network management should be unified within a single administration package. In a server-centric configuration, an administrator must contend with numerous servers with different administration packages, which increases the complexity of the operation. NAS administration should consist of user-friendly interfaces that enable adding and deleting users and groups, implementing security and access features, and providing hierarchical file histories to track the data demand and usage.
 
For NAS devices used in cluster configurations, an administrative option should be provided that allows centralized management. Remote administration should also be provided, via either a Telnet connection or Web-based interface.
 
Fault Tolerance/Reliability
 
The above features are necessary for most enterprises, but are of no comfort if a storage appliance is down. When a file server fails, its data is completely unavailable to the network; with an NAS configuration, server failure does not result in inaccessibility of data.
 
High reliability is perhaps the most critical feature to consider when purchasing an NAS device. Not all NAS devices are fault-tolerant. All critical hardware components must be redundant with transparent failover support for both the RAID and server components to virtually eliminate downtime.
 
As an increasing number of companies begin to see the value of NAS and a data-centric model of operation, more and more challenges and advantages come to light. It is critical to look for interoperability, value, capacity, and ease of installation and administration when evaluating storage needs.
 
Page Tagizad is Director of Product Management for Procom Technology, a leading manufacturer and pioneer in the development of network attached storage solutions. He can be reached at page_tagizad@procom.com.