Network Attached Storage

A Network Attached Storage (NAS) device is a server dedicated to file storage that lets you add hard disk space to your network. Large enterprises find NAS devices crucial because most models can hold terabytes of data and provide mission-critical reliability. Compared with a more traditional server-based approach, NAS appliances typically promise easy setup and administration.

In this Lab feature, I review five NAS devices—Compaq's TaskSmart N2400, LSI Logic Storage Systems' MetaStor N4300, Network Appliance's NetApp F840, Procom Technology's NetFORCE 1500, and Raid-tec's RAIDserver V—that range from small, relatively inexpensive units to high-end, full-featured, and highly scalable units. All five units support both the Common Internet File System (CIFS) and NFS file-sharing protocols, for Windows users and UNIX users, respectively.

In considering systems for this review, I limited the field to NAS systems that offered a minimum of 400MB of disk storage. Although IBM and Hewlett-Packard (HP) offer NAS solutions, both vendors declined to participate in this testing. IBM is developing a new product line and couldn't provide production versions of the new systems. HP offered no explanation for its choice not to participate.

Feature Overview
The TaskSmart N2400 meets midrange to high-end NAS requirements and is the only tested system based on Windows 2000—Win2K Advanced Server, to be exact. Compaq licenses Win2K from Microsoft, so you don't need a Client Access License (CAL) to use the TaskSmart N2400. (Windows Services for UNIX—SFU—2.0 makes TaskSmart N2400-based data available to NFS users.) The TaskSmart N2400 consists of a 3U (5.25") rack-mount server—dual 733MHz Pentium III processors with a 133MHz front-side bus and 256MB of Level 2 cache—with 1GB of Error-Correcting Code (ECC) SDRAM. The server also includes an embedded Smart Array controller with two 18.2GB disk drives configured as a RAID 1 array (i.e., mirror set) for the OS. A four-channel Compaq Smart Array 4200 Ultra 2 RAID controller and as many as four storage cabinets support 2TB of storage. Each storage enclosure holds as many as fourteen 18.2GB or 36.4GB disk drives. Other standard features include an embedded Ethernet interface and a Compaq Remote Insight Lights Out Edition Board (RIB). The TaskSmart N-Series Console program, a Microsoft Management Console (MMC) based application, centralizes access to the system's administrative tools. The SnapShot Manager allocates and manages storage volumes and point-in-time views of data called snapshots. I reviewed a 1TB system that contained four storage enclosures—for a total of fifty-six 18.2GB Ultra 3 SCSI 10,000rpm disk drives—and a four-port 10/100 Ethernet interface.

The MetaStor N4300 is a high-end Sun Microsystems Solaris 7.0 based NAS solution that boasts the processing power of two or four 400MHz UltraSPARCII CPU modules. The system I tested had four CPU modules and nineteen 18GB Ultra 2 SCSI disk drives in three drive trays. Redundant SCSI channels service each drive tray, and redundant RAID controllers that share the six SCSI channels provide high availability. You can configure the system with as many as four storage controllers and eighty 18GB, 36GB, or 73GB disk drives for a maximum storage capacity of 5.85TB. TotalNET Advanced Server (TAS) technology lets the MetaStor series participate in mixed-mode (i.e., combined Win2K and Windows NT) domains and exposes MetaStor storage to Windows users.

The NetApp F840 enterprise filer is a high-end, highly scalable file server for Windows, UNIX, and Web clients. The appliance offers a maximum storage capacity of 6TB and a standard 3GB of ECC RAM. Network Appliance's proprietary Data ONTAP OS, a UNIX-based microkernel, provides excellent CIFS performance. On the version I tested, I was able to join an NT domain but not a Win2K domain. Network Appliance claims that Data ONTAP 6.1 (which should be available by the time you read this article) will provide full Win2K support. I tested a minimally configured system that contained seven 36GB 10,000rpm disk drives that were fibre channel connected at 100MBps. I tested the appliance once with four 10/100 Ethernet NICs, and again with one Intel Gigabit Ethernet NIC, which Network Appliance says is the most common network configuration that the company ships. Data ONTAP implements software-based RAID 4 for data-storage fault tolerance.

The NetFORCE 1500 is a single-cabinet midrange NAS solution that supports as many as ten 18GB, 36GB, or 73GB disk drives for a maximum capacity of 730GB. The system I tested contained a 700MHz Pentium III processor, 512MB of server RAM, and ten 36GB 10,000rpm disk drives. The system can join mixed-mode domains and includes an easy-to-use Web-based administration utility.

The RAIDserver V is a midrange solution that supports as many as 24 Ultra 2 Low Voltage Differential (LVD) disk drives in two 4U (7") rack-mount cabinets with a dual-channel Ultra 2 SCSI RAID controller. The system contains a 32-bit 266MHz PowerPC 750 CPU and a 64-bit bus interface. You can configure the RAIDserver V with as much as 512MB of system RAM. The system software is a Raidtec-enhanced version of the Linux 2.2 kernel. I tested a tower-cabinet model that contained twelve 18GB disk drives and 320MB of system RAM. The system can join mixed-mode domains.

Installation
Because these devices are storage appliances, you might expect a Plug and Play (PnP) installation and setup experience. However, each solution requires that you perform an installation and configuration procedure to establish a network connection, define storage volumes, and make the storage accessible to Windows or NFS clients. Some of these products include a setup process that's easy to understand and to successfully complete. Others give you a complex interface and nonintuitive or ill-documented steps to successful implementation.

TaskSmart N2400. Win2K AS was preinstalled on the first of three logical volumes on the RAID 1 mirror set connected to the server's integrated RAID controller. Although you can operate the TaskSmart N2400 through the RIB's Web interface, I attached the system to the Lab's Raritan keyboard/video/mouse (KVM) network and used the Win2K console interface to complete the initial configuration.

After easily cabling the TaskSmart N2400's components together and connecting the appliance to the network, I powered it up. Manually configuring the server, getting it on the network, and verifying proper operation were simple. Although manual configuration is a perfectly valid method of setting up the TaskSmart N2400, Compaq recommends that you use the TaskSmart Appliance Server Utility CD-ROM, part of the Reference Information kit that comes with the system. The CD-ROM includes a wizard that helps you collect basic server-configuration information and writes this information to a Configuration Data Diskette. When a factory-fresh system boots for the first time, it uses the information on the Configuration Data Diskette to automatically configure the TaskSmart N2400.

To review the typical end-user experience, I used the TaskSmart QuickRestore CD-ROM to restore the TaskSmart N2400 to its factory-fresh state. I ran the TaskSmart Appliance Server Utility on my Win2K Professional desktop and filled in the wizard's forms—supplying names for the server and the RIB—and the network adapter configuration information. Using this method to get the system up and running was quick and easy.