NAS Advantages: A VARs View

Posted on April 01, 1998

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NAS Advantages: A VAR`s View

Potential benefits of network-attached storage (NAS) include faster data access, easier administration, and no-brainer configuration.

Ron Levine

Don Schrenk, a storage consultant with Direct Connect Systems, a value-added reseller in Marietta, GA, has specialized in providing network storage solutions to Fortune 1000 clients for more than four years. InfoStor recently talked with Schrenk to get his thoughts about the advantages of NAS and how it can be implemented in a range of environments.

Why is NAS gaining popularity?

Network administrators are always on the lookout for dependable, expandable, and easy-to-install options to alleviate server storage overload. NAS fills the bill. Basically, NAS removes the file-server function from overloaded general-purpose servers. It does this via a specialized, high- performance network-attached file server, sometimes referred to as a "filer."

On a network, data-access time determines how rapidly you can do your job. For instance, how fast securities traders process orders, how quickly product designers can get their wares to market, and how promptly corporate intranet users can download a file depends, in part, on data-access time. NAS devices ensure users fast and reliable access to data.

What are some of the factors to consider before implementing NAS?

The first thing you look at is how many users you have on the system. Are there enough users to justify [buying a NAS device]? Next, you look at what the users are doing when they log onto the server, because if you have 50 clients and all 50 need to log onto the same Unix machine, they have to go through seven million lines of code essentially to get to their data. What that does is place an undue overhead on that machine. It`s supposed to be number-crunching, but it can`t because you have clients trying to access their data. That`s when you consider using a NAS device to offload those clients.

When is NAS not a good idea?

If a customer tells us they need absolute 100% fault tolerance, I may not recommend NAS. Instead, I`d probably use dual-redundant servers with more than one network interface so there is no single point of failure.

What makes NAS devices so easy to install?

It`s a specialized dedicated appliance designed to perform one function only--file access and storage--so it`s not a complicated device. At Direct Connect Systems, we`re most familiar with Network Appliance`s NetApp Filer because we`ve used it as a storage solution for a number of our clients, but all NAS devices are similar in this respect.

Filers come with their own circuit boards, embedded software, and power supplies. The NetApp Filer simply plugs into a 10-BASE-T, 100-BASE-T, FDDI, ATM and/or Gigabit Ethernet LAN. Once installed, the applications never notice it.

How do you get it going?

It`s almost automatic in a Unix, Windows, or combination environment. Once plugged in, you wait a few minutes for the embedded software to detect and configure to your existing system. Then, it looks like any other server on your network. We`ve found that NAS servers easily integrate into LANs as an extension of the main servers` hard-disk capacity. Because the NetApp filer does not have proprietary hardware (it`s based on Alpha or Intel processors and an EISA bus), has a simplified operating system designed just for file serving, includes a RAID storage configuration and component redundancy, its reliability approaches 100% uptime.

You mainly work with Fortune 1000 clients. What are these companies most concerned with once the NAS server is up and operating?

The questions we most often get concern backup, administration, and various application issues.

What are the appliance`s backup capabilities?

Reliable data backup is essential to any disaster prevention plan and is a major concern to our clients. The NetApp Filer supports three file backup methodologies: the filer`s "dump" command, support for NDMP [Network Data Management Protocol], and backup across NFS or CIFS platforms. The "dump" command is similar to the familiar Unix "dump" command. NDMP is a standard by which an enterprise backup system--such as Veritas` Netbackup, IBM`s ADSM, or Legato`s Networker--can direct the backup of the NetApp Filer. The third backup method supported is a straight NFS or CIFS backup. Here, the Filer is backed up as if it were local disk space to the NFS or CIFS client station.

How does a NAS server ease system administration issues?

This is another reason why these devices are so popular. As an example of their simplicity, the NetApp Filer we install has just 39 commands and a small group of configuration files, making it extremely easy to maintain and administer. Filer administration can be accomplished through the serial console connection, a telnet connection across the TCP/IP network, or through the FilerView GUI using a Java-capable Web browser. Administrators usually require less than a half day to learn how to fully operate and administer the Filer.

Sounds easy, but are there risks to running user applications?

The NAS server provides file service--that`s all. The application actually runs locally to a compute server that has accessed the filer using NFS mounts or CIFS shares. Now, there are some applications that prevent their data from being stored on a network-attached drive. But if your application can utilize disk space accessed across the network, it will run on the NetApp Filer or other NAS devices.

Because you`re most familiar with the NetApp Filer, what are some of its key features?

-The WAFL (write anywhere file layout) file system, which reduces drive bottlenecks.

- The Data ONTAP operating system, which contains only 300,000 lines of code. This is extremely efficient compared to Unix or NT with millions of lines of code.

- Full read-ahead caching on files less than 100K in size.

- Native multi-protocol support. The NetApp filer currently supports NFS (Unix), CIFS (NT and Windows), and HTTP, allowing for file sharing across LANs.

- RAID-4 configuration to ensure data protection.

What`s an example of a recent NAS installation you`ve done for a client, and what were the advantages?

One client of ours, ADTRAN Inc. in Huntsville, AL, is a designer and manufacturer of transmission products. They had a network storage problem, and the NetApp Filer provided the perfect solution. The huge CAD files used by the company`s engineers were negatively impacting overall network performance and were close to utilizing full network storage capacity. Not only was a network storage bottleneck near, but exacerbating the problem was the fact that Unix and Windows NT users could not share files. What they needed was a common pool of disk storage that would keep more files on-line and allow full file sharing across the enterprise. NAS provided added capacity for all users across the network, and it`s also extremely reliable; a lost CAD file is something that ADTRAN can`t tolerate.

The key benefits for ADTRAN were file sharing, reliability, high-speed performance, and ease of administration. And because it supports multiple-protocols, Unix and NT users can share stored files without using any emulation software on the clients. We installed a NetApp Model F520 Filer with 80GB in a RAID-4 configuration. Since then, ADTRAN has added another 80GB. The additional drives were easy to install--just slide them into the drive shelf and execute a single command. In seconds, the usable disk space was doubled. Today, ADTRAN has about 40 users accessing the Filer over a Fast Ethernet LAN--mostly engineers storing large CAD files and backup file indices on the NAS device. The filer, which is available 24 hours a day, also supports remote access.

Click here to enlarge image

NetApp`s multiprotocol architecture provides native support for NFS, CIFS and HTTP, which eliminates the overhead and compatibility issues sometimes associated with emulation software.

Ron Levine is a freelance writer in Carpenteria, CA, and a regular contributor to InfoStor. Direct Connect Systems can be contacted at (770) 933-9327 or by visiting their Web site at www.directconnect.com.


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