What are the advantages and disadvantages of digital linear tapes (DLT) vs. CDs? Why would I select one over the other, and in which cases would this happen?
It is difficult to fairly compare both technologies, as they have very different specifications and usages. For example, DLT media offers far greater capacity than any optical media. SDLT tapes will hold 160 GB of uncompressed data compared to less than 1 GB for CDs and under 9 GB for the highest capacity DVDs. Therefore, for large data storage capacity requirements, tape technology is clearly the right choice.
Performance is also very different when comparing both technologies. SDLT tape drives can accommodate native data transfer rates of approximately 16 megabytes per second (MBps) in comparison to a write speed of about 5 MBps for high-capacity DVDs.
It might be argued that CD/DVD technology can produce read-only, unalterable copies of data for compliance requirements. However, many DLT tape solution vendors now offer Write Once Read Many (WORM) capabilities with their DLT tape subsystems.
The one advantage left for CD/DVD-type technology is its low cost, which makes it a popular solution for organizations with a small IT footprint and low data storage capacity requirements. Such companies, who often cannot justify the cost of deploying larger automated tape solutions, sometimes find CD/DVD technology an attractive data protection alternative.
This was first published in April 2005