Hewlett Packard StorageWorks SDLT 160/320 Review

Bottom-Line: The small external footprint of the SW SDLT 320, coupled with the high backup capacity, admirable performance, and SCSI design, make this HP SDLT design a highly desirable drive.

I am a Network Engineer responsible for a medium sized server farm (approximately 125 servers), and the business utilizes a number of tape backup solutions including a number of small internal and external medium to high capacity drives for backing up legacy systems. The last of these stand-a-lone drives is a single Hewlett Packard StorageWorks SDLT 160/320 (external) Tape Backup Unit (TBU).

The business utilizes one SW SDLT 320 TBU to provide back-up services for a vital legacy system one SDLT tape cartridge.  The SW SDLT 320 is a single drive TBU designed to utilize SDLT technology and SDLT 160GB /320GB tapes.  SDLT tape drives are fully read and write backwards compatible with all DLT-III/IV and other SDLT tape cartridge products from all licensed manufacturers.

Even thought the SW SDLT 320 is an external unit it is small and fits neatly onto a standard rack; in fact three units could fit side-by-side on the rack, a testimony to the compact design of the TBU.  And since it is an external SCSI device, the SW SDLT 320 not only will work with HP Compaq ProLiant and AlphaServer systems, but other server systems from other manufactures as well.  Our one external SW SDLT 320 is mated with an HP Compaq ProLiant DL380.  The HP Compaq ProLiant uses a Low Voltage Differential (LVD) Ultra 2 SCSI interface for data transfers.  Care should be taken never to connect a LVD device to a High Voltage Differential SCSI card; a malfunction will most certainly result.     

My Viewpoint

Thus far the technology has delivered on the promise of ever expanding backup capacity; SDLT 600, which is capable of backing up 300GB native, and 600GB compressed, is the latest in a long line of SDLT tape formats, most of which were developed by Quantum Corp.  The ultimate goal is to store up to 1.2TB of uncompressed data onto a single SDLT cartridge with transfer rates of up to 100MBps uncompressed. Other formats of SDLT include SDLT220, and SDLT320.

The business uses the SW SDLT 320 to perform nightly (excluding weekends) unattended full /differential backup's utilizing a one SDLT-320 (160GB/320GB) tape changed out on a daily basis (by yours truly), generating a total of 5 tapes per week.  The unit performs at or around the stated back rate of at some 16MB/s (uncompressed), 32MB/s (compressed).

After loading the tape into the unit, all other manipulation of the drive; tape mounting, formatting, tensioning, erasing, ejecting, and tape preparation is easier handled by the tape backup software.  The grayish SW SDLT 320 has only one front panel control, the eject button with which you can manually eject the tape.  Also on the front of the unit is the hinged door for inserting a tape along with three status LED's for power, tape loaded, and activity.  On the back of the unit, there is an Ultra Wide SCSI LVD connector port, a recital for power, and the power switch.             

The small external footprint of the SW SDLT 320, coupled with the high backup capacity, admirable performance, and Ultra 2 SCSI design, make this HP SDLT design a highly desirable drive. With a maximum back-up capacity of 320GB, the SW SDLT 320 would be the ideal solution for the small to medium sized business.  And the backwards compatibility allows the business to use regular DLT-IV tapes. 

Though the business utilizes a very large capacity free-standing tape library for primary backups, our (1) SW SDLT 320 Tape Backup Units is an indispensable piece of our overall backup strategy.