Data storage guru Henry Newman points out that the importance -- and headaches -- of the continual migration to tape storage. As he notes "tape migration is one of the biggest issues in the tape community, if not the biggest."
Tape used for computers has been around for about 60 years. That makes the technology older than most and far older than most of the people working in the industry today. Since the backup market for tape is now a far smaller percentage of the market than the archive market, tape migration is one of the biggest issues in the tape community, if not the biggest.
Data migration for large archives is often a continual process. Two key reasons for this are that:
- Tape densities increase every 18 to 24 months at about a 2x rate, but tape performance increases at about 20 percent. This means the time to migrate archives takes longer and longer without an increased number of tape drives.
- Tape drive interface, such as Fibre Channel 1 Gb and 2 Gb, are no longer supported. Without migration, more tapes libraries will be required a significant cost.
Given these reasons and others, migration to new tape technologies is an ongoing process and migration must include other hardware such as servers, RAID storage and switches.
Migration used to be pretty straightforward, but there are many reasons why this is no longer the case. I am aware of very few sites that have migrated backup data, but everyone I work with knows they must migrate archive data. Backup data for the most part is transient. Yes, Sarbanes-Oxley requires saving some data, but the amount most companies have that falls under its jurisdiction is minuscule. Moreover, tapes can be read for five years, so you can just put them in cold storage.
The size of this type of data compared to the size of archive data, such as medical records, the Hubble space telescope or things like NOAA satellite images, is tiny. Today, every car and airplane built must have all of its structure model data and design information archived in case of a problem. In the not too distance future, our genome will be stored. Large archives are growing faster than tape density and much faster than tape performance. Currently, density for LTO nearly doubles while performance increases 20 percent or so. ???? Per year? Per month? -- time period ??? Many sites take more than a year to migrate archives from Old Tape Drive X to New Tape Drive Y. Archive software now available makes that easier migration from archive software Vendor A to Vendor B, but for vendors that do not use proprietary tape formats, this is a smoother process. I am not even going to cover this, as it is so vendor dependent. Tape media migration is difficult enough, and it takes careful planning to ensure everything goes smoothly.
Here are factors to consider:
Depending on the archive software, as many as four types of hardware must be evaluated as part of migration planning from old tape drives to new:
Read the rest about data storage and tape migration at enterprisestorageforum.