Backup Tapes Should Not Be Used for Archiving Data

It amazes me how many organizations use backup tapes for archiving. Backup tapes and the software systems that create them were never designed for archiving, and any archiving strategy dependent upon backup tapes is fraught with cost and risk.

Backup systems and the backup tapes they create are designed for data protection - copying large amounts of data to protect against failure. In the event of inadvertent data deletion, disk failure, system crash or loss of an entire data center, backup tapes can restore data very quickly. The tape backup processes are mainly about speed, indiscriminately copying large amounts of data at a point in time onto high-capacity tapes. Backup systems do not have much understanding of the type or content of data that resides on their tapes. Backup tapes are quite good at...backup.

Record retention and legal hold, on the other hand, require archiving. Archiving - the selective retention of information for an indeterminate period of time - is a different function than backup. Archiving systems either target a particular media such as e-mail, files or database, or some combination of these, recognizing data not as a stream of bytes but rather as "objects." Furthermore, archiving systems often maintain additional information about the data being retained, usually the data type, content, retention period, etc. Archiving systems have important capabilities beyond backup systems, including fast search and retrieval, deleting a single document or systematically suspending the deletion of a group of documents.

While it is easy to start archiving using backup tapes, this quickly creates problems. Every backup cycle creates another copy of the data, exponentially increasing the cost of searching and restoring documents. Furthermore, after a number of years, backup tapes become difficult to read, and as such are not acceptable for long-term retention.

Organizations should rethink their backup tape strategy:

  • Many organizations are moving away from tape-based backup systems to disk-based systems that allow faster access to information and avoid redundant copies of data.
  • Where tape-based backup is still used, segregate data from different systems into different tape pools. This simple step can quickly narrow the search for relevant data.
  • Dedicated archiving systems for e-mail, files and structured data can be a big win.
  • Don't forget to search for and clean out older, unneeded backup tapes on a regular basis. If the tapes are redundant, and the data isn't under any type of hold - get rid of it.

Legal and IT should review data retention strategies regularly. What you don't know can hurt you.

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