Notes on DAT tape drives

We have had very positive experience with DDS DAT tape drives, and can recommend them for their reliability.

• Advantages:
  • blank tapes are cheap
  • the tape drive unit is quiet
  • tapes do not require retensioning
  • most (if not all) DAT drives feature hardware compression

• Disadvantages:
  • the tape drive units are more expensive than Travan

At our offices, we use a Seagate DDS-3 DAT drive which has served us well.

Effectiveness of hardware compression

Our independent tests have shown that on average, you can expect a 1.4:1 or 1.5:1 compression ratio when backing up a file server (including system files).

Thus, you can expect the following tape capacities:

• DDS-2: 4 gig native, approximately 6 gig compressed
• DDS-3: 12 gig native, approximately 18 gig compressed
• DDS-4: 20 gig native, approximately 30 gig compressed

Compression ratios will vary depending on the type of data.