Disk-Based Backup Appliances Go Head-to-Head

Are disk-based backup appliances ready for prime time? Here's what our reviewer thinks.

Adam Carhedan

June 27, 2005

13 Min Read
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Any IT pro who has designed a backup scheme knows that backup is complicated. You need to consider issues such as incremental versus differential backup, retention periods, backup windows, and point-in-time recovery, among many others. Of course, backup involves not just copying data but also restoring it, and restoring from tape can be difficult and error-prone. Backup ought to be simpler, especially for small-to-midsized businesses (SMBs) that have limited IT resources.

In the wake of Microsoft's recent release of Windows Storage Server and the advent of Serial ATA (SATA) disks, I anticipated seeing disk-based backup innovations to simplify backup and restore and finding good deals on backup appliances for SMBs. I found four backup-appliance solutions that include all the hardware and software necessary to back up Windows servers to disk. (For a list of additional vendors of backup-appliance products, see the sidebar "More Backup-Appliance Vendors.") Each vendor also offers optional tape backup or replication for offsite storage, open-file support, and agents to enable backup of Microsoft Exchange Server and Microsoft SQL Server data.

Each solution takes a different approach to backup. When developing ratings, I considered each product's ease of use, functionality, price, and expandability. Table 1 provides a detailed comparison of the products' features. I gave the solution that had the best balance of these factors the Editors' Choice award, but the products that received lower ratings might also be good choices for you if low-cost offsite backup is a priority or if you can trade off functionality for simplicity.

Tandberg Data's InteliNAS appliance is a 1U (1.75") rack-mountable device that runs Windows Storage Server. You can control the appliance's file-sharing functionality through a Web-based interface, but the backup functionality requires you to access the Windows GUI. For those who haven't used Windows Storage Server, it operates like any other version of Windows but has behind-the-scenes optimizations for storage. InteliNAS is sold with VERITAS Software's VERITAS Backup Exec as an add-on, which you can use to manage disk-to-disk backups and restores and migrate backups to tape if you purchase an optional tape drive or autoloader. Given VERITAS's large market share, many readers might already be familiar with its products' rich functionality, ease of use, and support for both disk- and tape-based backups. The familiarity of both Windows Storage Server and Backup Exec make InteliNAS a compelling solution. However, Tandberg Data has done little in the way of enhancing the combo to simplify backup.

Before I could back up data to the InteliNAS appliance, I had to configure Backup Exec's storage parameters. Tandberg Data provides only minimal support for Backup Exec, so I decided to dive into the manual myself. I learned that backing up to disk requires creating an aptly named Backup-To-Disk folder by simply selecting a location on the hard drive. Backup Exec treats Backup-To-Disk folders as devices (as it does tape drives). I created multiple Backup-To-Disk folders and put them in a device pool, to let backup jobs run in parallel, as Figure 1 shows. I also organized storage into media sets (i.e., a group of media that share a retention period). Although Backup Exec is generally easy to use for an enterprise-class backup solution, I felt a bit overwhelmed by the amount of documentation I had to read before performing my first backup.

Next, I pushed agents to the machines I wanted to back up, selected a backup schedule policy, and performed both a backup and a restore of about 150GB of data. Backup Exec installed agents from the InteliNAS console. For my backup scheme, I chose from three VERITAS-designed backup policies—Daily Full, Weekly Full and Daily, or Monthly Full with Weekly and Daily—that determined how much historical data I could recover. Because I was backing up to disk, Backup Exec let me choose synthetic backups, which save bandwidth by building a full backup from previous full and incremental backups. In addition to backing up files, Backup Exec supports backups of the registry, system state, and Active Directory (AD). Restoring data was also straightforward; Backup Exec located all the appropriate disk backups to restore without user intervention.

Backup Exec provides standard alerting and reporting capabilities. Reports helped me identify failed jobs and skipped files. Although I didn't obtain the optional tape drive with the InteliNAS appliance, Backup Exec includes reports to determine which tapes should move between the library and vault.

Tandberg Data does little preconfiguration of InteliNAS, but Backup Exec's ease of use and functionality complement the appliance, and the two products make a good combo. However, I found the bundled solution offered nothing to simplify backup beyond its individual components.


Contact: Tandberg Data * 800-726-1800Web: http://www.inostor.comPrice: $6434SummaryPros: Add-on backup software (VERITAS Backup Exec) is functional and familiar to many IT pros; good priceCons: Vendor provides minimal configuration; product requires support from two different vendorsRating: 3.5 out of 5Recommendation: InteliNAS is a good bundle at a great price; it's perfect if functionality and price are priorities over simplicity.

Exabyte E-Z D2D2T
Exabyte, Snap Appliance, and BakBone Software have bundled an Exabyte tape library, a Snap Appliance NAS device, and BakBone's NetVault backup software into two 1U (1.75") devices sold as a single backup-appliance bundle, called the Exabyte E-Z D2D2T (for "disk-to-disk-to-tape"). The Snap Appliance device runs BakBone's NetVault 7 for Guardian OS, a Linux derivative, but you manage the appliance through a Web-based UI. The Snap Appliance product comes with NetVault 7 installed and preconfigured with 500GB of disk space dedicated to a virtual tape library (VTL). NetVault is licensed by capacity for VTL support, though, so you'll have to purchase additional licensing from BakBone to fully use the available disk space for backup. Inclusion of tape as a standard feature makes E-Z D2D2T a great value if offsite storage is a requirement, but NetVault's VTL licensing limit and limited backup automation made backing up somewhat complicated.

Although NetVault is installed on the Snap Appliance device, I had to install a second copy of NetVault on my own machine to manage the instance on the Snap Appliance device. Like Backup Exec, NetVault requires you to install a client on each machine that will be backed up. NetVault doesn't perform remote installations, but it does come as a Windows Installer (.msi) package, so you can distribute it through Group Policy. Defining NetVault backup jobs is similar to doing so by using Backup Exec, and NetVault lets you back up client machines' file systems as well as the registry, system state, and AD.

Unlike using Backup Exec's backup policies, creating a backup scheme via NetVault is a manual process. In addition to letting you choose the type and schedule for each backup job, NetVault supports a feature called duplication, which the dialog box in Figure 2 shows. This is where the D2D2T part comes in. BakBone and Exabyte technical support walked me through their recommended configuration, which used duplication to create a disk-based backup on the VTL and roll it to tape.

BakBone and Exabyte tech support worked well together to get my solution working. E-Z D2D2T hadn't yet been officially released at the time of testing, so my experience might not be representative. However, Exabyte plans to provide first-level support for the entire bundle and work directly with both BakBone and SnapAppliance for second-level support.

Like Backup Exec, NetVault also includes alerts and reporting to monitor backups. I successfully configured SMTP email alerts; however, all alerts go to a single email address, and you can't alert different people for different backup jobs. NetVault's restore process is also similar to Backup Exec's and required no user intervention as long as the necessary backup tapes were in the library.

E-Z D2D2T is the only bundle I reviewed that includes everything necessary for offsite backup without requiring an additional purchase. Additionally, considering Exabyte's plan to provide well-organized support and a competitive price, E-Z D2D2T is a compelling choice. NetVault's manual backup-planning process and a licensing scheme that prevents me from fully using my available disk space for backup are too significant to ignore, however. I recommend E-Z D2D2T only if your priority is moving tapes off site over the speed and simplicity of disk-based backups.

Exabyte E-Z D2D2T

Contact: Exabyte * 800-392-2983Web: http://www.exabyte.comPrice: $6375SummaryPros: Tape support standard; great NAS supportCons: Use of more than 500GB of disk for backup costs extra; product requires you to configure a backup scheme manually; email alerts go to only one addressRating: 3 out of 5Recommendation: The Exabyte E-Z D2D2T is a good value for the price if you need offsite backup and can spend the time to develop a backup scheme.

STORServer D1 Backup Appliance
The STORServer D1 Backup Appliance comes as a tower or rack-mountable device. You can add a rackable shelf for a total of 6U (10.5") of rack space and up to a 6TB capacity. The appliance runs Windows Storage Server, so you can access and manage it just like any other Windows machine.

The D1 is bundled with IBM Tivoli Storage Manager. TSM is the epitome of functional but complicated backup software, but don't let that scare you. TSM comes installed and preconfigured by STORServer. To back up a server, all I had to do was deploy a Windows Installer-based client agent from a file share on the appliance. The client was automatically added to a backup schedule that performed an initial full backup and daily incremental backups between 8:00 p.m. and 4:00 a.m. Performing a restore was equally easy. Just as STORServer's default configuration managed the backup schedule, TSM managed location of the necessary incremental backups. However, I had to perform the restore from the machine I was restoring to instead of via the D1 console.

The D1 also includes STORServer Manager (SSM), a software component to help manage TSM. The SSM console, which Figure 3 shows, let me identify failed jobs, warnings, skipped files, and other potential problems with TSM. SSM includes an alerting feature that I configured to send me an email message when a job failed or when the disk was getting full. STORServer sells technical support as an add-on to the D1 appliance. The support employees are knowledgeable and fully support the D1 appliance, SSM, and TSM.

TSM includes open-file support at no additional charge. Although the TSM configuration was simple and wizard-based, I discovered that the current version of TSM supports Microsoft Volume Shadow Copy Service (VSS) to back up the system state only and not other types of data on a volume. TSM's native open-file technology, Logical Volume Snapshot Agent, doesn't currently support Windows Server 2003. This was disappointing, though it's likely a temporary drawback, as future versions of TSM will fully support Windows 2003.

The D1 has almost everything I originally set out to find. It's a complete hardware and software solution, and the hardware is expandable. TSM is functional enough to meet complex backup needs, but STORServer made simple configurations easy and error-free. The D1 isn't the lowest-price solution I considered, although it's competitively priced. I give the D1 four diamonds and the Editors' Choice award because it has the best balance among ease of use, advanced functionality, and price of the four products I reviewed.

STORServer D1 Backup Appliance

Contact: STORServer * 888-786-7765Web: http://www.storserver.comPrice: $7159SummaryPros: Easy out-of-the-box backup operation; supports up to 6TB capacity; STORServer supports all componentsCons: Limited open-file support; large form factor; additional agents are pricey; no remote restore capabilityRating: 4 out of 5Recommendation: The STORServer D1 Backup Appliance provides a wonderful combination of ease of use, advanced features, and support. I give it the Editors' Choice.

Intradyn takes a much different approach to its 1U (1.75") RocketVault backup appliance from the other appliances I tested. It's a true appliance because all required hardware and software reside on the device. The RocketVault backup appliance operates without agents and lets you back up an unlimited number of computers without buying additional licenses. For offsite storage, it can replicate backups to RocketVault appliances over the network by using block-level differencing (based on the Rsync utility) so that only changes consume valuable bandwidth. RocketVault's agentless model can't back up everything you might need to protect, though, and the solution is expensive compared with the other products I reviewed.

RocketVault runs the FreeBSD OS and accesses remote data for backup via Windows shares instead of an agent. Given the appropriate credentials, RocketVault can back up your entire hard disk by using administrative shares (hidden shares named $), but it can't back up open files, the registry, system state, or AD. Intradyn's BackAgain software can use RocketVault's storage to back up such data, but BackAgain requires an agent and isn't typically sold as part of the RocketVault solution. If you're willing to back up your system state and other such data to local disk by using other tools, such as NT Backup, you might find RocketVault a useful solution.

RocketVault's simple Web-based UI, which Figure 4 shows, makes backup easy. I started by defining groups of shares from various computers on my network, then scheduled backup for each group. RocketVault supports only three preconfigured backup schemes—daily, weekly, and monthly—but this simplicity makes the product easy to use. RocketVault's excellent documentation explains what points in time each schedule lets you recover to and advises you on how much disk space you'll probably need for each schedule.

If you want to back up only user data and not the full system, RocketVault's true-appliance model makes for an easy backup solution. If you ever decide you need more advanced backup capabilities, though, you'll have to buy additional software and set up all new backup schemes. Although Intradyn succeeded in making backup simple, I didn't like RocketVault's missing advanced functionality or high price tag and therefore give RocketVault 2.5 of 5 diamonds.


Contact: Intradyn * 651-203-4600Web: http://www.intradyn.comPrice: $14,995SummaryPros: Agentless, simple product; provides network replication for offsite backup; well-written documentationCons: Requires additional software to back up registry, system state, and Active Directory or add application support; expensiveRating: 2.5 out of 5Recommendation: RocketVault makes backup very easy, but the simple backup process doesn't capture open files, system state, or AD, and the product is expensive. The product might serve your needs if you need an easy-to-use solution to back up only data files.

No Perfect Solution
Having tested all four solutions, I found that no appliance fully automates backup and restore operations; providing reliable backup still requires time and effort from an IT pro. The STORServer D1 Backup Appliance comes with most of the work done for you, but STORServer Manager only thinly veils TSM's complexity, so I recommend purchasing the tech support. InteliNAS with VERITAS Backup Exec is easier to use, but a diligent IT pro must thoroughly test the self-configured backup scheme. Intradyn's RocketVault is the easiest to use of the products, but it doesn't provide the system state and AD backups that Windows sites require. Exabyte's D2D2T Solution, which includes a tape autoloader as a standard feature, was the most complete bundle, although it also took the most work to manage. Although I'd consider buying a backup appliance, I look forward to the market producing even better solutions in the future.


We were unable to obtain products from some of the vendors we contacted for this comparative review. If you're looking for a backup appliance bundle, you might also try these companies:

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