Storage on the quick

Step-by-step guide to buying the right entry-level network-attached storage system


A small office looking to quickly upgrade its storage capacity may want to consider an entry-level network-attached storage device. A NAS box is an array of hard disks and a built-in server that attaches directly to an Ethernet network. It provides a manageable, shared resource for file-based storage.

Organizations shopping for NAS devices will find multiple flavors and a variety of prices, even among starter devices. The selection ranges from $800 boxes to $20,000-plus systems. Capacity, processing power and feature sets vary widely from box to box, so buyers must carefully evaluate their present and future requirements before making a purchase.

Fundamental purchasing considerations include the intended application of the NAS device and the number of concurrent users. Other factors to weigh include scalability, data protection and the availability of disaster recovery features. Future developments to keep an eye on include encryption and the emergence of serial-attached SCSI (SAS) drives.

1. User environment: Small workgroup or large branch office?

Buyers should consider what they plan to do with NAS and the type of environment in which it will operate before purchasing a solution.

Organizations that need only small storage capacity may opt for ultra low-end NAS machines that cost about $1,000 for 1 terabyte of storage. Products in this category often employ an embedded Linux operating system. Keenan Baker, a storage specialist at CDW Government, cited Buffalo Technology's TeraStation NAS product as an example. A 1 terabyte TeraStation was recently selling on CDW-G's Web site for $966.99.

Anthology Solutions' Yellow Machine, which also uses embedded Linux, costs about $1,000 for 1 terabyte of storage. The product supports as many as 50 PCs, although most of the company's customers have 5 to 20 PCs, said Ted Theocheung, vice president of marketing and business development at Anthology.

Customers, however, are not using this class of NAS to support a bunch of users,
Baker said, because such products generally lack the processing punch to sustain large numbers of concurrent users.

Large branch offices that need file services for scores of users can move upstream to NAS machines with faster processors and more memory. But the price tag increases with performance. Expect to pay at least $3,000 for a more powerful system.

2. Scalability: Growth strategies
Larger offices may place a higher premium on the potential to grow NAS capacity. A number of vendors offer NAS solutions that cost $3,000 to $10,000 and offer greater performance and expandability.

A number of these devices run Microsoft Windows Storage Server 2003, while others from vendors such as Adaptec use proprietary operating systems. Baker said devices in this tier are scalable, a property the cheapest NAS devices lack. He said Hewlett-Packard's DL100 G2 Storage Server is an example of a Microsoft-based NAS appliance. It is expandable through an external drive shelf. Adaptec's Snap Server 520 can also expand via an external drive shelf, he added.

NAS vendors have moved to boost scalability. Adaptec, for example, introduced the Snap Server 550 in February. The server can expand from 1.2 terabytes to 43.2 terabytes.

Scalability was one factor the Santa Clara County, Calif., government considered when purchasing a NAS appliance from Sun Microsystems' Data Management Group. The county's Tax Collector's Office uses a Sun StorEdge 5310 appliance for data archiving. The system has a 1.5 terabyte capacity, but the office can add additional modules.

'The storage demand is not there yet, but it will be eventually,' said Frank Baldevarona, information systems manager at the Tax Collector's Office.

As agencies purchase larger-capacity systems, they should explore thin provisioning, said William Hartman, vice president of technology and architecture at Sanz, a storage consultant and systems integrator.

'We believe very strongly in a thin-provisioning engine in a NAS appliance,' he said.

Here's how thin provisioning works and why it's important. Hartman said that in a Windows environment, only about 25 percent to 30 percent of the NAS capacity provisioned to a particular server or application is actually in use. For example, an organization may need 25G of storage for a database but will purchase 750G of capacity with the notion of growing into it, he said.
In comparison, thin provisioning, also referred to as capacity on-demand, lets administrators create and provision, for example, a 6 terabyte storage volume without buying and installing 6 terabytes of disk. An organization could start with 1 terabyte of storage and pay for additional increments as necessary.

This method can save small organizations a considerable sum of money, Hartman said. Customers 'don't purchase as much upfront, just what they need,' he said.

IBM's N3700 NAS appliance, which is a rebranded Network Appliance machine and the company's entry-level N series box, provides thin provisioning through FlexVol technology, said John Foley, IBM's worldwide product marketing manager for N series products and NetApp alliance manager. The feature 'lets customers grow or shrink volumes as they need them,' he said.

The IBM device's price ' $25,345 for a 1 terabyte configuration ' includes the cost of the FlexVol feature.

3. Backup: High-demand area

Many organizations are seeking to supplement ' or replace ' tape with increasingly affordable disk, and NAS products offer backup functions for a range of prices.

Among products in the $1,000 range, Anthology's Yellow Machine lets customers perform fast full-image or file/folder backups of desktop and laptop PCs. EMC's Retrospect Pro software comes with the product. Theocheung said Retrospect Pro includes a scheduling capability that automates the backup process.

'People are starting to see that NAS is a good value play for backing up remote office servers and laptops,' said Steven Rodgers, director of technical marketing at Adaptec.

Adaptec's Snap Server NAS appliances include BakBone Software's NetVault Workgroup Edition software. Snap Server supports other third-party backup applications, too.

Another backup consideration: Many NAS appliances have SCSI ports, so they can connect directly to a tape drive for easy data archiving, Baker said.

4. Data protection: From RAID to snapshot

NAS products offer Redundant Array of Independent Disks as the baseline for data protection. RAID guards against data loss caused by drive failures. But vendors offer additional features ' some standard and some optional ' to provide greater protection.

Anthology, for example, incorporates disk scrubbing in addition to RAID as a standard component of Yellow Machine. Disk scrubbing provides ongoing monitoring of disk data integrity. Theocheung said enterprise-class NAS devices often feature such technology.

Viruses can also delete or corrupt data. Tape backups have served as the traditional means of restoring data, but many organizations now opt for the disk-based snapshot approach. Frequent point-in-time snapshots of data provide multiple recovery points and faster restore times.

'The key to data protection is snapshot capability,' Hartman said. 'If you have a virus or a hacker or...a user who dumps the database, you have to recover data to a point in time before the event occurred.'

Some NAS products offer snapshot capability, but customers will likely have to look beyond low-end products, analysts said.

Rod Mathews, senior director of NetApp's Competitive Program Office, said the company's customers rank snapshot capability among their top priorities when purchasing NAS solutions. He said organizations deploying NAS in remote offices prefer the quick recovery from local snapshots in the event of data loss or corruption.

5. Replication: Disaster insurance
Remote replication represents the next line of data protection after local snapshots. In this disaster recovery approach, a NAS device at the primary site mirrors data to another device at an off-site location. Baker said agencies interested in remote replication can easily establish the capability with two NAS devices and replication software.

The approach, however, adds some cost to the configuration, often $2,000 to $4,000 to the total cost of a NAS deployment, Baker said. Replication is usually an optional feature.

NAS can provide inexpensive shared storage for a small workgroup or enough headroom and special features to keep a branch office happy. But as with everything else in life, you get what you pay for.

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