Network-Attached Storage
4. Network-Attached Storage Versus Storage Area Networks
5. NAS Solutions for Today's Business Issues
7. Summary - NAS Filers Serve e-Time Storage Needs
1. Introduction
The torrents of information storming in and out and through today's businesses could hardly have been foreseen when the first computer systems achieved desktop status. These units came equipped with the storage capacity of a goldfish bowl, by today's standards. Building on this early direct-attached storage architecture, IT departments soon answered increasing information demands with general-purpose servers and direct-attached storage, typically attached using a SCSI high-speed interface. Now, these processing and storage initiatives are hard pressed to support and direct the monumental data requirements of ERP, MIS, and data warehousing for today's companies.
Thanks in a large part to the Internet, today's information influx does not stop. Data is created, transmitted, stored, and delivered around the clock. And both internal and external customers are becoming more dependent on rapid, reliable access to company data. Those companies that are not yet Net-operational feel the pressure to get there, fast. This scenario also leaves Internet and applications service providers as well as dot-com organizations scrambling for reliable, scalable solutions. Overall, businesses need to meet skyrocketing storage needs and they'd like to do so without an exponential increase in IT talent-professionals who are difficult to find and expensive to hire. Network-Attached Storage (NAS) may be the answer.
2. What is a NAS Device?
Network-attached storage (NAS) is a concept of shared storage on a network. It communicates using Network File System (NFS) for UNIX« environments, Common Internet File System (CIFS) for Microsoft Windows environments, FTP, http, and other networking protocols. NAS brings platform independence and increased performance to a network, as if it were an attached appliance.
A NAS device is typically a dedicated, high-performance, high-speed communicating, single-purpose machine or component. NAS devices are optimized to stand alone and serve specific storage needs with their own operating systems and integrated hardware and software. Think of them as types of plug-and-play appliances, except with the purpose of serving your storage requirements. The systems are simplified to address specific needs as quickly as possible-in real time. NAS devices are well suited to serve networks that have a mix of clients, servers, and operations and may handle such tasks as Web cache and proxy, firewall, audio-video streaming, tape backup, and data storage with file serving.
This paper introduces readers to a category of NAS devices called filers. These highly optimized servers enable file and data sharing among different types of clients. It also defines NAS benefits with respect to storage area networks (SANs). Finally, the paper introduces Sun Microsystems' entry-level NAS device, the Sun StorEdge N8200 filer.
3. What is a Filer?
NAS devices known as filers focus all of their processing power solely on file service and file storage. As integrated storage devices, filers are optimized for use as dedicated file servers. They are attached directly to a network, usually to a LAN, to provide file-level access to data. Filers help you keep administrative costs down because they are easy to set up and manage, and they are platform-independent.
NAS filers can be located anywhere on a network, so you have the freedom to place them close to where their storage services are needed. One of the chief benefits of filers is that they relieve your more expensive general-purpose servers of many file management operations. General-purpose servers often get bogged down with CPU-intensive activities, and thus can't handle file management tasks as efficiently as filers. NAS filers not only improve file-serving performance but also leave your general-purpose servers with more bandwidth to handle critical business operations.
Analysts at International Data Corporation (IDC) recommend NAS to help IT managers handle storage capacity demand, which the analysts expect will increase more than 10 times by 2003. Says IDC, "Network-attached storage (NAS) is the preferred implementation for serving filers for any organization currently using or planning on deploying general-purpose file servers. Users report that better performance, significantly lower operational costs, and improved client/user satisfaction typically results from installing and using specialized NAS appliance platforms." (Source: Taming the Storage Growth Beast with Network-Attached Storage (NAS), ¨2000, International Data Corporation.)
4. Network-Attached Storage Versus Storage Area Networks
Some people confuse NAS with storage area networks (SANs); after all NAS is SAN spelled backwards. The technologies also share a number of common attributes. Both provide optimal consolidation, centralized data storage, and efficient file access. Both allow you to share storage among a number of hosts, support multiple different operating systems at the same time, and separate storage from the application server. In addition, both can provide high data availability and can ensure integrity with redundant components and redundant array of independent disks (RAID).
Others may view NAS as competitive to SAN, when both can, in fact, work quite well in tandem. Their differences? NAS and SAN represent two different storage technologies and they attach to your network in very different places. NAS is a defined product that sits between your application server and your file system (see Figure 1). SAN is a defined architecture that sits between your file system and your underlying physical storage (see Figure 2). A SAN is its own network, connecting all storage and all servers. For these reasons, each lends itself to supporting the storage needs of different areas of your business.
NAS: Think Network Users
NAS is network-centric. Typically used for client storage consolidation on a LAN, NAS is a preferred storage capacity solution for enabling clients to access files quickly and directly. This eliminates the bottlenecks users often encounter when accessing files from a general-purpose server.
NAS provides security and performs all file and storage services through standard network protocols, using TCP/IP for data transfer, Ethernet and Gigabit Ethernet for media access, and CIFS, http, and NFS for remote file service. In addition, NAS can serve both UNIX and Microsoft Windows users seamlessly, sharing the same data between the different architectures. For client users, NAS is the technology of choice for providing storage with unen-cumbered access to files.
Although NAS trades some performance for manageability and simplicity, it is by no means a lazy technology. Gigabit Ethernet allows NAS to scale to high performance and low latency, making it possible to support a myriad of clients through a single interface. Many NAS devices support multiple interfaces and can support multiple networks at the same time. As networks evolve, gain speed, and achieve latency (connection speed between nodes) that approaches locally attached latency, NAS will become a real option for applications that demand high performance.
SANs: Think Back-End/Computer Room Storage Needs
A SAN is data-centric - a network dedicated to storage of data. Unlike NAS, a SAN is separate from the traditional LAN or messaging network. Therefore, a SAN is able to avoid standard network traffic, which often inhibits perfor-mance. Fibre channel-based SANs further enhance performance and decrease latency by combining the advantages of I/O channels with a distinct, dedi-cated network.
SANs employ gateways, switches, and routers to facilitate data movement between heterogeneous server and storage environments. This allows you to bring both network connectivity and the potential for semi-remote storage (up to 10 km distances are feasible) to your storage management efforts. SAN architecture is optimal for transferring storage blocks. Inside the computer room, a SAN is often the preferred choice for addressing issues of bandwidth and data accessibility as well as for handling consolidations.
Due to their fundamentally different technologies and purposes, you need not choose between NAS and SAN. Either or both can be used to address your storage needs. In fact, in the future, the lines between the two may blur a bit according to Evaluator Group, Inc. analysts. For example, down the road you may choose to back up your NAS devices with your SAN, or attach your NAS devices directly to your SAN to allow immediate, nonbottlenecked access to storage. (Source: An Overview of Network-Attached Storage, ¨ 2000, Evaluator Group, Inc.)
5. NAS Solutions for Today's Business Issues
IDC predicts that by 2003, more than $6.5 billion will be spent annually on NAS storage solutions. (Source: Taming the Storage Growth Beast with Network-Attached Storage (NAS), ¨ 2000, International Data Corporation.) The analyst group believes the demands of Internet service providers, application service providers, and dot-coms for reliable, cost-effective, and rackable systems will help drive the proliferation of NAS solutions.
Decreased IT Staff Costs
On the front end, businesses welcome extreme amounts of information and strive to manipulate it for use in real time. On the back end, IT professionals, with their current infrastructures, scramble to accommodate the exponentially increasing data burden. General-purpose servers, especially, require large amounts of skilled personnel time to solve storage and file access challenges.
In contrast, a NAS device requires little IT staff time and effort. Management is accomplished through a graphical user interface (GUI) in a Web browser, which enables NAS access from anywhere on the network. Since a NAS filer is preconfigured to support specific file-serving needs, administration is simplified, and this ease of use results in fewer operator errors. Also, because more capacity can be managed per administrator with NAS than is possible with general-purpose server storage activity, the total cost of ownership is lower.
Scale Fast, Without Downtime
Dot-coms and other rapidly scaling companies endeavor to make sure their IT infrastructures keep pace with their dynamic business realities. Building on the structure of your general server or servers may be required in some business areas. But burdening these servers with escalating storage needs can be ineffective and run counter to your accelerated business practices. As you add capacity for your general-purpose server, you'll face downtime. When you bring the system down to increase its storage, your business applications will be unavailable, which may slow-if not halt-productivity.
On the other hand, expanding storage with NAS is simple and nonintrusive. You can install a new filer within 15 minutes as opposed to hours or days required to install or add traditional storage. More advanced NAS devices can increase storage on-the-fly, eliminating the need for you to add another node on your network. This means your users access what they need when they need it, responding in real time to a marketplace that demands immediate action.
Relief for Your Server
A NAS filer helps by offloading tedious and bandwidth-consuming file serving tasks from your server. This allows your server to use its power to process your data with improved availability and performance.
Have you checked your general-purpose server's workload lately? If it is handling file serving activities, chances are it is handling too much. You face increased risk of latency when your general-purpose server must complete high-priority file serving tasks while handling applications, electronic mail, and a myriad of other critical business tasks.
Multi-OS Connectivity and Data-Sharing
Whether your company is busy merging or acquiring, or simply growing, you will no doubt face the demands of a heterogeneous operating environment. A NAS device can answer this challenge with its capability to serve two chief operating system camps: NFS (UNIX) and CIFS (Microsoft Windows). One of the undeniable strengths of NAS is its capacity to support these protocols and allow for cross-platform data sharing. This is an increasingly important attribute as the business usage of data-intensive application files such as digital media (audio, video, and photography) becomes more common.
Leveraging Existing Infrastructure
By adding NAS nodes to your network, you can leverage your network investment and your current network administration skills. NAS can be deployed on your network anywhere it is needed. It also can be integrated with larger management tools, like Microsoft Management Console, Tivoli, and HP Openview, allowing you to maximize your use of these products. And NAS does not require costly network operating system (NOS) licenses.
Often, IT centralization is asked to simplify responsibilities and conserve company efforts, but it accomplishes neither if remote branch and satellite offices must operate without IT support. NAS can help you realize the intent of centralization by allowing you to add storage in a remote office and manage it via the Web-based GUI from anywhere on your network-including your central/home office. This means you can reap higher performance from existing infrastructure at the remote office and keep management "at home."
Transparent Backup
Another benefit of NAS is its transparent backup activities. Filer backup can be completed without affecting the performance of your general-purpose or application servers. Your CPU does not have to calculate what to back up and when. Simply direct your filer to complete backup at a specific time and it will use industry-standard procedures to complete this task.
6. NAS and Sun
The concept of attaching storage devices to a network is not new. About 20 years ago, the Remote Procedure Call (RPC) protocol enabled this break-through. RPC meant computers could share not only storage files and devices across the network, but also printers and other hardware, software, and resources. Sun Microsystems embraced the RPC concept in 1984, when the company developed the remote file and device-sharing application protocol, Network File System (NFS).
The Precursor: NFS
NFS gives all network users access to files that may be stored on different types of computers. In a client/server scenario, NFS enables computers connected to the network to operate as clients to access remote files. The same computers also can act as servers by allowing remote users to access their files. In other words, NFS makes files stored on a file server accessible to any computer on a network and eliminates the need to transfer files between users. The advantages of using NFS include:
Streamlined access. Users can work on just what they need. They can work on a piece of a file instead of the entire document.
Transparent remote access. Remote files appear to be local to your users, and they need not complete a file transfer before use.
Up-to-date data. Because file access protocols directly procure the server's file, the file data are always current.
Real-time access. Data can be provided to an application as soon as it arrives from the file server.
Sun opened NFS technology to the public, and over the years this technology has become a standard for introducing network interoperability among heterogeneous systems.
Sun StorEdge N8200 Filer
NAS has the same objective as NFS, which is to improve data access while reducing overhead and downtime. Building on these concepts, Sun is intro-ducing the Sun StorEdge N8200 filer, the first product in the Sun StorEdge N8000 filer product family. This entry-level NAS device is preconfigured with integrated hardware and software to address your file serving needs.
Installation of the Sun StorEdge N8200 filer can be completed in as little as 10 minutes. You simply connect the filer directly to your network and answer several questions online to make your new storage available. Sun streamlined installation time to allow you to make storage available to your users as soon as possible. Because the Sun StorEdge N8200 filer also optimizes your TCP/IP stack for low latency and uses a 10/100-BaseT Ethernet connection, you are able to provide your users with truly fast storage access.
With the Sun StorEdge N8200 filer, you can increase storage capabilities with 200 GB expansion arrays up to 800 GB per filer (capacities Sun expects to double in coming months), with the comfort of RAID 5 hardware. This frees the CPU from having to make parity calculations, and results in better performance. For example, if a disk fails and/or a disk needs to be rebuilt, performance impact is minimal.
The flexibility inherent in the Sun StorEdge N8200 filer lets you gain more capacity vertically, by adding more storage to your filer, or horizontally, by adding more filers to your network-all without taking your network down. Compared to the price of adding traditional storage, the modular, extensible architecture of this filer offers affordable versatility. You pay only for what you need, when you need it.
Plus, the Sun StorEdge N8200 filer supports heterogeneous environments by running NFS for UNIX-based clients and CIFS for Microsoft Windows users. You can consolidate and serve files for both UNIX and Microsoft Windows workgroups from this filer.
System Management and Structure
Ease-of-use is the chief attribute of the Sun StorEdge N8200 filer's management design. This filer's Web-based administration tool, with its user-friendly GUI, simplifies such tasks as adding users, groups, hosts, or shares. If your site uses NIS or NIS+, then the GUI is used only to manage the hosts and shares.
This solution is built on the Sun Solaris operating environment and is complementary to server and storage hardware from Sun. The Sun StorEdge N8200 filer consists of a dual-CPU controller and hardware RAID disk storage arrays with the previously described Web-based GUI administration. Two spare PCI slots are available for additional network cards or other resources. Additionally, Sun StorEdge N8000 filer product family software provides a simple configuration and tunes the Sun StorEdge 8200 filer for optimum NFS performance.
In the Sun StorEdge N8200 filer, Sun builds not only on its history of establishing NFS, the protocol that has become the industry standard for network interoperability, but also on its technology fundamentals. Scalability, reliability, availability, and serviceability are as inherent in this filer as they are in the full spectrum of Sun server and storage products.
7. Summary - NAS Filers Serve e-Time Storage Needs
Focusing processing power solely on file service and storage, NAS filers can serve any business or technology workgroup-from software design to CAD to service providers/dot-coms to engineering-that requires low cost, scalability, and high-performance in a file server. NAS also can work in tandem with your SAN environment, handling network file serving needs while the SAN tackles back-end storage tasks. Unobtrusive and accommodating, filers meld with your existing infrastructure and facilitate data sharing across heterogeneous operating environments.
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