Enterprise Backup Software

Data that you store on enterprise networks represents money, and for most organizations, irrecoverable loss of such data would be a financial catastrophe. Thus, choosing the correct backup software is like picking the right vehicle to take your company's receipts to the bank: You want the armored car, not the Yugo. Unfortunately, differences between backup software applications are not as apparent as this analogy suggests. The five enterprise-level backup applications I tested—Computer Associates' (CA's) ARCserveIT Advanced Edition 6.61, Syncsort's Backup Express 2.1, VERITAS Software's NetBackup 3.2, Legato Systems' NetWorker 5.51, and Tivoli Systems' Storage Manager 3.7.1—can deliver network data to storage media. But differences appear in the applications' performance, ease of use, scalability, manageability, and cost.

Defining the Enterprise
For software testing purposes, I defined an enterprise network as a network that has more than 300GB of data to back up within one time window. An enterprise network also has multiple network OSs (although the main backup software runs on a Windows NT 4.0 server) and at least one active mail server. Using this definition, I assembled a test network on which various servers ran NT (one of the NT servers ran Microsoft Exchange Server 5.5), Novell NetWare 5.1 and NetWare 4.11, and Sun Microsystems' Solaris 7. I generated and dispersed several diverse data sets that totaled approximately 350GB in more than 1 million files.

The Test Network
In my test network, the server that hosted the backup software was a Data General AViiON 3704 with four 550MHz Pentium III Xeon processors, 2MB of Level 2 cache, and 4GB of RAM. Disk storage consisted of thirty 18GB 10,000rpm disks in an EMC CLARiiON fibre channel disk array. I configured these disks in five RAID 5 arrays of 66.1GB each. I used one array to store performance-monitor logs and other dynamic data that was not part of the data sets I backed up. For network connectivity, the server hosted two Adaptec ANA-6944B four-port 10/100 Ethernet 32-bit NICs. I used NSI Software's Balance Suite 2.71 for Windows NT to aggregate the eight ports into one IP address for transmit-and-receive load balancing. The tape library's SCSI connectivity relied on dual Adaptec AHA-2944UW Ultra HVD 32-bit adapters.

The robotic tape library was an Advanced Digital Information Corporation (ADIC) Scalar 1000 with four DLT 7000 tape drives and 158 tape slots (for more information about the Scalar 1000, see "Scalar 1000," page 152). I divided the tape drives evenly between the two SCSI adapters in the host server. I loaded the tape library with 29 DLTs and two cleaning cartridges. Between tests, I cleaned the drives.

Service Pack 5 (SP5) ran on all NT servers in the test. The NT servers' drives used NTFS and had less than 2 percent fragmentation.

Three network clients ran on Dell Precision WorkStation 410 systems; each system had dual 550MHz processors, 128MB of RAM, and on-board Adaptec 2940 U2W SCSI host adapters. Each workstation came with a 4GB SCSI disk, and I added three Seagate Cheetah 9GB 10,000rpm hard disks to each system to increase storage capacity. I configured the first system as an NT file server and configured the Cheetahs and system disk as four logical drives. I filled the system with nearly 29GB of data. I set up the second system with NetWare 5.1, configured each physical drive as a separate NetWare volume, and filled the system with 22GB of data. I used the third system for my Exchange server. I used RAID 0 to stripe the three 9GB disks and created a logical drive to hold the 16GB private Information Store (IS) and directory database. I added a 9GB disk to the third system for the 6.5GB public IS.

To create another NT file server, I added a Hewlett-Packard (HP) NetServer E45 that had a 266MHz Pentium II processor, 128MB of RAM, and an Adaptec AHA-2910C SCSI host adapter with three HP 4.2GB 7200rpm disks. I used one disk for the OS and configured the other disks as a RAID 0 stripe set to create an 8GB logical drive. I filled the logical drive almost to capacity with random data.

For the NetWare 4.11 server (Support Pack 8a), I used a Digital PC 3000 with a 300MHz Pentium II processor and 128MB of RAM. In this system, I installed an Adaptec AAA-131U2 PCI RAID controller and attached a Cheetah 9GB 10,000rpm hard disk. On this drive, I created a NetWare volume and loaded it with 7.2GB of data. The Solaris 7 server was a Sun Enterprise 250 server with dual 400MHz 64-bit UltraSPARC processors, 2GB of RAM, and six 9GB 10,000rpm hard disks configured as a RAID 5 volume. I loaded the Solaris 7 server with data totaling 31.5GB.

For the network, I used a 16-port autosensing full-duplex 10/100 switch with 1MB buffers to link the servers to eight aggregated ports on the Data General backup server. All servers communicated at 100Mbps full duplex. Figure 1 illustrates the test network.

Results
Price will be a big factor in your enterprise backup selection. Pricing for enterprise backup products is complex and environment-dependent. Table 1 shows vendor-supplied prices for licensing products on various system configurations. These numbers are for comparison only; contact vendors for detailed price quotes for your environment.

Each enterprise environment has unique complexities and requirements, and a product that is well suited to someone else's environment might not work as well on yours. When you evaluate a product, you need to consider scalability, support, performance, features, ease of use, and cost. Scalability means that a product can grow as your enterprise grows without burdening your IT staff with complex reconfigurations or the need to change backup products altogether. Good vendor support is usually worth much more than any cost savings you might realize at purchase. Differences in the quality of support you receive from vendors can define your downtime, which directly affects your bottom line and your peace of mind.

No product emerged as a strong favorite for enterprise environments. Taking into consideration all the test factors, including scalability and support, I give the overall edge to Backup Express for its excellent performance and midrange pricing. I place NetBackup second for its stability and scalability.

The Test
The products I tested supported a range of autoloaders and advanced features (e.g., the ability to span media and support parallel backup data streams from one client). Each product also offered Storage Area Network (SAN) support. Table 2 compares the products' important enterprise backup features.

I gave the vendors details of the test network and the test procedure and asked the vendors to recommend ways to optimize their products' performance. I tested each product's ability to simultaneously back up 349GB of data on the entire server farm. This test roughly simulated how a 9:00 a.m.-to-5:00 p.m. business would attempt to back up a large volatile data set after hours. To measure performance, I timed the backup job and recorded processor utilization. I then restored 151GB of backed-up data, timed the restore operation, and checked data integrity. Figures 2 and 3, page 138, compare the products' backup and restore performance, respectively.

ARCserveIT Advanced Edition 6.61
ARCserveIT, originally a NetWare and UNIX backup product, supports client agents for Windows 9x, Windows 3.x, NetWare, OS/2, Macintosh, and various UNIX platforms. The product has advanced autoloader support and supports several database agents. CA aims ARCserveIT Advanced Edition 6.61 at companies that use NT as a platform for backup servers. CA designed ARCserveIT to work as a component within the company's Unicenter TNG, a larger enterprise-management product, but ARCserveIT is fully functional as a standalone product. Although ARCserveIT supports features such as centralized backup-database administration, ARCserveIT is a two-tier server and client product and won't scale as readily as some of the other products I tested. ARCserveIT requires NT 3.51 or later, 32MB of RAM, and 40MB to 50MB of disk storage. The product came on a CD-ROM, and a startup guide accompanied it. The CD-ROM included more documentation in Portable Document Format (PDF) files.

I launched the install wizard from the CD-ROM and chose a complete installation. ARCserveIT gave me the option of installing Microsoft SQL Server rather than ARCserveIT's proprietary database, Raima. A CA technical support engineer said the Raima database holds 16 million records (although a patch enables it to contain unlimited records), and installing a SQL database lets you expand beyond 16 million records. By default, the Raima database installed on my test system. After choosing the rest of the defaults, I rebooted the server and ran the device configuration wizard. ARCserveIT identifies SCSI tape drives at the device level and automatically sets configuration parameters. The device configuration wizard recognized the Scalar 1000 and the Scalar 1000's barcode reader. Then, because I had chosen the autoconfigure option, the wizard configured the drives and robot. ARCserveIT let me designate a clean tape slot and set the cleaning interval (clean-tape configuration wasn't this easy in the other products I tested). Finally, ARCserveIT verified the media in the tape library.

ARCserveIT includes a client push agent and uses push technology to improve data-transfer performance between server and clients. After the client receives a backup request, it pushes data across the network in large-packet bursts. The ARCserveIT host server breaks up the large packets and formats them for transfer to the designated storage device. These processes, which improve performance, occur simultaneously between the client and server.

Installing the push agent was easy and quick. In the initial ARCserveIT install wizard, I chose the option to install client agents remotely. The install wizard launched its remote setup executable file (rsetup.exe) and displayed all the Windows clients on my network. I chose the clients on which I wanted to install the agent, provided a domain account and password under which the ARCserveIT agent would run, specified the target directory to install the client files, then clicked OK. The installation process completed in a few minutes. After the initial setup completed, CA notified me that I needed to install SP1 to ARCserveIT. The update process was as simple as the installation was.

ARCserveIT's Exchange Server backup agent uses the Exchange Server's backup and restore API functions to back up an online database. The backup agent can also use Messaging API (MAPI) functions to perform online mailbox-level backup and restore. Although mailbox-level backup and restore is appealing, it doesn't provide disaster recovery or replace full Exchange database backups. The Exchange Server backup agent installed quickly and easily from the server program CD-ROM. On the server, the Exchange Server client appeared with the appropriate Exchange database options in the network client directory tree, which Screen 1 shows.

ARCserveIT's UNIX client installation was fast and uneventful. I mounted the ARCserveIT CD-ROM, then used the pkgadd command to transfer the appropriate Solaris client files to the server. I launched uagentsetup from the server's client directory and accepted the default setup options. Finally, I launched the agent with the uagent start command. On the server, the UNIX client appeared under the client tree hierarchy.