What is NAS ?
A NAS device is a server that runs an operating system specifically designed for handling files (rather than block data). Network-attached storage is accessible directly on the local area network (LAN) through LAN protocols such as TCP/IP.
NAS components
NAS appliances serve files in heterogeneous environments. The result is efficient access to data, regardless of where you're located in the organization or which devices comprise the network. The following several components make a NAS efficient:
A dedicated server: Usually a thin server within the storage device, the server has its own network address and allows all of the computers on the network to access the storage device without involving a host server. So, to some extent, the network is completely circumvented. For example, when the network experiences outages, users can still access data through the NAS appliance without being affected by the status of the network.
A thin server is a server with just the basic software and hardware to perform a specific function.
A network connection: This is typically an Ethernet connection. The connection to the LAN or WAN allows access to data from all points on the network without consideration to where the user making the request actually resides on the network.
Software: This provides a range of services. The most typical of those services are access to storage, storage I/O (input/output) processing applications, RAID (redundant array of independent disks) storage control, security, administration, and monitoring.
A NAS appliance is connected directly to a network and provides file-level access to data using standard data access protocols. The data stored in a NAS appliance is accessible to users across the organization, as well as to application servers, and remote servers that have access to the network. The file system the NAS appliance uses is determined by the location of the data that is requested by the application client and whether it's in a cache or in storage.
For complete efficiency, the NAS appliance usually occupies its own node on the network. In such a configuration, the single appliance (server) handles all the data storage on the network, taking the load off of the application or enterprise server. This provides a high level of file consolidation, streamlines file access, and lowers the cost of managing storage.
Additional reductions in cost can be found in the fewer pieces of hardware required. With fewer devices to manage, fewer problems occur, even when multiple NAS appliances are needed to accomplish efficient storage.
In future posts you'll find out how to determine whether you need a single NAS appliance or multiple NAS appliances to meet your storage needs.
NAS hardware and software
NAS hardware is fairly straightforward. The NAS device is a self-contained, Plug and Play unit that connects directly to the network and, in most cases, can be installed and configured in 15 minutes or less. That ease of installation is the answer to every busy IT manager's prayers. However, there are other advantages to NAS, such as the following:
High availability: Many NAS appliances have fault-tolerance capabilities or clustering functionality built in.
Scalability: NAS appliances scale easily in both capacity and performance.
Universal connectivity: NAS appliances typically allow for multiple network connections. This enables more users to connect to a common storage element at any given time.
Data sharing: One of the most basic functions of NAS is heterogeneous data sharing via the built-in file-sharing capabilities.
Storage management: NAS storage management is centralized and the administration of system management is simple. One advantage of this simplified management is the increase in capacity that can be managed by each administrator.
Most NAS devices also have a set of core software features that power the solutions. Those core features are the operating system, management capabilities, and universal connectivity, and although the specifics of these core features differ according to vendor, a basic set of core features comes packaged with most NAS appliances.
Operating system
The operating system is preinstalled on the NAS appliance and can affect how the device is deployed. The three most common operating systems are Microsoft Windows Storage Server 2003, Unix/Linux, and NetWare. The operating system that you select depends on your organization's preferences and business needs.
Management capabilities
Most NAS appliances have preinstalled management capabilities, usually accessible via a web browser. These management features mean that managing NAS is flexible and can be accomplished from any location with web access.
Universal connectivity
One of the most attractive features of NAS is the ability to access files using a variety of disparate file protocols. This ability means that you don't need to acquire any additional seat licenses, and each different existing server (or even multiple servers with different operating systems) doesn't need its own storage box.
Additional software features
In addition to the core software features of NAS devices, most vendors also offer a variety of advanced, value-added software capabilities. These capabilities are pick and choose, according to the specific needs of your business. It's in the pick-and-choose features that you begin to differentiate the low-end NAS installation from the mid-grade and high-end NAS installations. Your specific business needs and vendor offerings determine which advanced software features are appropriate, but some of the extended features are:
Server clustering: In some cases, you want to configure your storage solution to include more than one NAS appliance, but you want all of the NAS appliances to act as one unit. Server clustering is the capability that enables this feature. You should consider using server clustering if high availability is required. If your data is mission critical, or if having a temporary outage of your organization's NAS appliance could stop the normal workflow of your business, multiple NAS devices and server clustering are combined to create a redundant solution that assures you'll never have downtime. When clustered, if one NAS device fails, other NAS devices in the cluster pick up the slack.
Data replication: This is a protection technology that creates a complete mirror image of all the data located on one NAS appliance to a second NAS appliance. After the initial mirroring is completed, only the changes to the data are synchronized at the time of the change. If a network failure or outage occurs and data needs to be restored quickly, an exact, easy-to-access replica of that data already exists.
Data snapshot: Occasionally, a user accidentally deletes a file and, in some cases, the IT department (or IT person, as the case may be) has to be called in to recover the deleted data. This situation can be time-consuming, frustrating, and costly. However, having the ability to take a data snapshot mitigates that expenditure. A data snapshot is a point-in-time copy of all data on a NAS device that is duplicated and stored on another NAS device or other backup media. The snapshot can then be accessed from individual workstations as needed, without getting IT involved.
A NAS solution is pretty straightforward, and that's one of the reasons that it's one of the fastest-growing storage technologies in the United States at this time. However, there are instances in which a single NAS appliance won't do the job.
