Getting A Grip On NAS Appliances.

The computer industry occasionally treats NAS--Network Attached Storage devices--like SAN's poor stepchild, but with IDC expecting NAS revenues of $5.1 billion by 2003--an annual compound growth rate of 55%--Cinderella should be so lucky. With this kind of money floating around, a lot of people are making a lot of NAS devices--or devices they're calling NAS. So many, in fact, that the Storage Networking Industry Association (SNIA) has formed a new NAS workgroup "dedicated to the development of education programs and standards for Network Attached Storage (NAS)." Their key objectives include defining a common terminology for NAS, developing accurate benchmarks, giving IT professionals a means to compare NAS devices, document and standardize CIFS protocol, identify NAS management strategies for network and system management environments, and establish NAS support across multiple platforms.

Compare the two definitions below:

* "NAS devices are dedicated, high-performance machines or components that stand alone and serve specific storage needs with their own operating systems and integrated hardware and software." Using this definition, Network Appliance's NetApp Filer, Quantum's entry level Snap Server, and Sun's new StorEdge N8200 are true NAS devices.

* "NAS is a storage architecture in which a storage device associates with multiple servers over a shared network. The storage is server-independent." The Aberdeen Group's definition widens the playing field to include such products as EMC's Symmetrix-attached Celerra, ADIC's StorNext NAS/tape library, and even StorageNetwork's SSP version of a NAS, NetPaks.

Whatever your definition, what should you look for in a NAS file server? The eight points listed below are a good starting point.

1. Easy installation and use. NAS devices are plug-and-play with default installations taking under 15 minutes. (Quantum's Snap Server takes five.) The NAS server should integrate into the existing network without interrupting other servers and there should not be additional server or client software to install. (This lets out EMC's Celerra, part of a comprehensive storage solution.)

2. Compatibility with existing networks. A NAS server should be compatible with your existing networking protocols and workstations. They should be server and operating-system independent and operate over established protocols such as TCP/IP, CIFS, NFS, and HTTP. The NAS server should also be able to share existing network security like NT Domain or NetWare Bindery.

3. Centralized administration. Most NAS devices offer browser-based management, allowing users to administrate the NAS from any client on the network or from anywhere on the Internet. A NAS device should have a graphical user interface and be relatively simple to maintain and install.

4. Cross platform file sharing. Most NAS servers will support UNIX and Windows NT clients. In environments that mix Windows, Apple Macintosh, and Unix/Linux workstations, their NAS solutions may call for network support for Microsoft, Novell, Apple, and Unix networks. It is, of course, possible to enlist separate NAS devices for the various protocols, but cross platform sharing is better for IT staff and users alike, as the device simply appears as a volume to the network user.

5. Backup. The NAS server should work with the organization's network backup application software. It might also be used itself as a backup device by using NAS-integrated tape devices to relieve backup traffic on the LAN by automating server backup functions.

6. Improved performance. Since all of a NAS' resources are optimized for file serving, it should offer superior performance over a general-purpose server.

7. High reliability. Since NAS servers have limited components and streamlined operating systems, they are often more reliable than I/O driven general-purpose servers. To ensure even more reliability, choose NAS file servers that support data redundancy with various RAID levels.

8. SAN-enabled Many higher-end NAS devices include a Fibre Channel port for a present or future SAN connection. This enables the NAS to utilize the SAN capabilities, including capacity expansion and storage management.

Network Appliance

Steve Duplessie of Enterprise Storage Group says about Network Appliance's NAS share, "To date, they are the king. EMC is hot on their trail and, so far, no one else is in the game.

Network Appliance's NAS solution is their NetApp Filer product. Network Appliance Filers are storage servers that utilize a highly optimized operating system on tightly integrated hardware. They are primarily slated for the midrange workgroup market, though Network Appliance is planning to make inroads into the high-end market as well.

* NetApp F760 is the line's enterprise server version, scaling to 1.4TB. It supports clustered failover for reliability and serves large-scale commercial and scientific applications, including database/ERP and consolidation of large amounts of heterogeneous data.

* NetApp F740 is a mid-range file server, well suited to software development, CAD, simulation applications and medium-sized ISPs. It supports clusters and scales to 900GB. It has many of the same features as the F760.

* NetApp F720 is a workgroup server that lacks clustered failover and scales to 464GB. It primarily serves dedicated user directories and ISPs, as well as small to medium-sized technical workgroups

Quantum

Serving the entry level or departmental market is Quantum's useful Snap Server. This NAS device installs in about five minutes and offers remote administration via the Internet, mixed platform connectivity for Windows, NetWare, Unix, Linux, and Macintosh, security integration with NT Domain Controller or Novell NetWare for pass-through user authentication, and industry-standard backup. Priced well below some other NAS offerings, it offers four models:

* Snap Server 4000/120GB with four drives and RAID 5 data protection. It sits two rack units high and can mount in a standard 19-inch rack or sit on a desktop.

* Snap Server 2000/60GB with two drives for small-to-medium workgroups. The dual disks are pre-configured with RAID 0 capability (striping, no parity) and can be configured to provide RAID 1 mirroring data protection or two separate volumes.

* Snap Server 2000/30GB with two drives serves small workgroups and remote offices. Like the 40GB model, the dual disks are configured to RAID 0 and can be configured to RAID 1.

* Snap Server 2000/15GB with a single drive is a portable server at three pounds. It can add storage to the network and is particularly useful for carting around data for software presentation, telecommuting and trade shows--sort of a Zip drive on steroids.

Sun Microsystems

Deliberately weighing in as an alternative to Network Appliance, Sun (the "It's the Storage, Stupid" company) has come out with the StorEdge N8000 family with 200GB to 800GB of capacity. Sun claims that its NAS device is faster and has a greater capacity than Network Appliance's F720, though the company has historically experienced less than stellar sales from its non-Sun connected devices. The N8000 offers a ten-minute installation process, scalable architecture, a simple graphical user interface, and a single 10/100-BaseT Ethernet for network storage performance. It allows file sharing in Windows and Unix environments. The higher capacity N8200 and N8400 will ship in September 2000.

EMC

EMC has a hybrid NAS product named Celerra, which requires Symmetrix Enterprise Storage to run. Using Fibre Channel, it's comprised of a cluster of dedicated file servers called Data Movers under a single point of control. Celerra offers scalability, which most other NAS devices do not (their major drawback), because of its connection to a SAN. Celerra allows dynamic file system growth and scales to multiple terabytes within the same cabinet. In addition, you can add additional Data Movers to directly scale performance.

Is it really a NAS? Not in the sense most people use the term, but it is a good addition to a planned or existing EMC installation. It can heighten the functionality of a Symmetrix system or give a direct-attach Symmetrix system accessibility via direct network access. As you might expect, Celerra serves the high end of the market.

ADIC

In April 2000, ADIC introduced a family of NAS appliances called StorNext. The models range from a capability of 950GB to nearly 24TB. Not surprising for a company known for automated storage libraries, it combines NAS technology with automated tape storage, making StorNext primarily a backup and retrieval device, since unmounted retrieval can run up to 60 seconds. (Mounted runs to 30 seconds and cached to less than one second.) With its active cache and real-time journaling, it can provide writing, browsing, and searching at disk speed. Users can manage files either through their normal file system tools or through an ADIC interface.

StorageNetworks

Storage service provider StorageNetworks has just released a new remote product named NetPaks. Working over their GDSN (Global Data Storage Network) NetPaks comes in two flavors, Base and Solo. NetPaks Base is a high availability clustered solution that offers dedicated network connectivity, redundant architecture with a SLA, guaranteeing 99.9% availability and 24x7 monitoring and management.

NetPaks Solo has a standard availability, lacking redundant architecture and 99.9% availability SLA. It is typically used for applications where the multiple copies of the data exist on the network or where data is strictly being used for test or development purposes.

This has been a quick tour through the wild and woolly world of Network Attached Storage. The future is positively luminous for the devices, whether dependent, independent, or remote. As the need for storage scales sharply upward, so does the need for straightforward solutions. However, the advantage of most NAS architecture is its Achilles heel: because it's easy to deploy, it's easy to misuse. Running out .of room? Throw on another device! Different workgroups have different devices? Oh well! But these kinds of cavalier attitudes will bite you not too far down the road. Make the NAS strategy part of an overall storage strategy for your customers and they'll be set for the long haul. And in the growing storage world, that will be a very long haul.