Imaging & Document Solutions - Test Drive September 1999

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Sony and HP DDS-4 Shootout

DDS tape is one of the most popular technologies for backup and archiving today. Although the tape drives can be expensive (in the range of $1,250 to $1,750), the tapes themselves are compact and inexpensive (at $10 to $35). This lets a DDS library store large amounts of data in a compact space at a relatively small cost.

DDS-4 increases the capacity of DDS tape to 20 gigabytes (GB) uncompressed, double DDS-3’s 10 GB. The cartridges are unchanged, but the tape inside is longer at 150 meters and the drives include new technology enabling higher data density. The two principal DDS tape drive manufacturers, Sony (www.sony.com/storagebysony) and Hewlett Packard (www.hp.com), have introduced DDS tape drives to take advantage of the new, higher density tapes.

We tested a stand-alone version of Sony’s new SDT-10000 drive. There is also an internal version that can be used in libraries and autoloaders. The drive has an eject button and three LED indicators for “Busy,” “Tape” and “Status.” I/O is through an Ultrawide SCSI port. The drive we tested was bundled with Yosemite Technologies’ TapeWare backup software.

The SDT-10000’s transfer rate is 2.36 to 4.72 megabytes per second (Mbytes/sec) with hardware compression engaged. In our tests we achieved better than 2.5 Mbytes/sec. This is very good performance, particularly for a “low-end” technology like DDS. Even with hardware compression turned off, record speed was better than 2.2 Mbytes/sec, nearly twice the rated 1.2 Mbytes/sec uncompressed record speed. Tapes loaded and ejected from the drive in less than 20 seconds.

Restore speed from the drive was slow, at about 1/3 Mbyte/sec. However, searches for individual files went quickly, limited only by the rewind speed of the drive. The slow read speed of the tape could be a problem if you’re archiving large files. If your files tend to be small, then the slower read speed is outweighed by the short time to data. The drive has full read and write compatibility with all older DDS tapes, a definite plus. We were able to read and write with DDS and DDS-2 tapes, and it will also handle DDS-3.

Hewlett Packard’s new DDS-4 drive is the SureStore DAT40. We tested a prerelease version, but by the time this article sees print, the drives should be available. Sony and Hewlett Packard both use generic SCSI cases, however, HP’s have a smaller footprint. Bundled software includes diagnostic utilities and Replica and Colorado backup software. Information and software is also provided for connecting the drive to Unix and Linux systems.

The SureStore DAT40 will be available in both internal and external versions. There are “Tape” and “Clean” LED indicators on the front panel along with an eject button. The SCSI port is Wide SCSI-2, slower than the Sony’s Ultrawide port, but it still supports low voltage.

It took about 20 seconds to load a tape and about 23 seconds to eject. Record speed was faster than the Sony at 2.7 Mbytes/sec. Read speed proceeded at an impressively fast 2.7 Mbytes/sec, more than eight times faster than the Sony drive. Properly configured for autoloaders and libraries, the DAT40 should make an excellent drive for archives as well as system backup. The DAT40 will read all older DDS tapes, but it cannot write to first-generation (90-meter) cartridges. It will write to DDS-2 and DDS-3 tapes.

The most interesting feature of the SureStore DAT40 is its “One-button Disaster Recovery.” Essentially, the DAT40 can emulate a CD-ROM drive in systems that have a CD-ROM boot-enabled BIOS. This lets you boot off a tape and is an excellent feature for workstations and servers, especially those where you have complex system folders larger than a single CD ROM’s 650 megabytes. With the disaster recovery feature, you can restart a system, reformat its hard drives and restore all files in a single step.

There are a number of requirements for disaster recovery. Your backup software has to be able to write the boot block to a tape. So far, only HP’s Replica software has this feature. Your server also has to have a compatible BIOS. In theory, a system that can boot off a CD can use disaster recovery, but you should check your server’s BIOS to see if it’s compatible. If it is, all you’ll need to do is keep the backup tape current, and you’ll never be more than a few minutes from a fully restored system.

—Lowell Rapaport

Editor’s Choice

We were impressed with both the Hewlett Packard DAT40 and the Sony SDT-10000. Backup times were very fast, and at 20 gigabytes, the capacity of a DDS-4 tape is large enough for just about any workstation or server. With the combination of data compression and a simple autoloader, DDS-4 should have no trouble backing up RAID systems or serving as the basis of a small tape archive.

Although both drives were flawless and fast, Hewlett Packard’s DAT40 was faster than the Sony during write operations and much faster when recovering files. This makes it a better drive for archiving regularly accessed files. HP’s One-button Disaster Recovery feature makes it a compelling drive for backup use as well. Better performance and extra features added up to an Editor’s Choice for the HP DAT40.

SureStore DAT40

Palo Alto, CA, 800-826-4111

Description: Internal or stand-alone DDS-4 drive

Tested Speed:

Write: 2.7 Mbytes/sec

Read: 2.7 Mbytes/sec

Compatibility:

Read: DDS, DDS-2, DDS-3, DDS-4

Write: DDS-2, DDS-3, DDS-4

Cache: 8 MB

Load/eject time: 20/23 seconds

Interface: Wide, Single-Ended, Low Voltage Differential SCSI-2