The Jukebox, or Near-line Network Storage Device

The Basic Concept of Near-line

On-line and Near-line are terms relating to storage devices on a network. Near-line storage is more cost effective than on-line storage although at the expense of a small time delay for retrieval.

The jukebox is a near-line storage device.

The concept of near-line storage is simple.
The analogy is your own office area.
You only want on your desk and in your desk drawers those bits of paper that are current or frequently used. The rest should all be neatly filed away in your filing cabinets and cupboards. The jukebox’s purpose is to hold the data that is either dead or hardly ever looked at, but which must be retained.
Pareto’s 80 – 20 law applies.

The reason you have near-line storage is to avoid keeping all of your data on-line, in the network server, which clogs up the network system, making it run slower, using up expensive RAID and Hard Disk space. In any case, RAID and HDD are not ideal storage devices for long term storage. The further benefit is that the back-up window is reduced by 80%, saving time, money, and tapes.

The process of selecting and sending files from on-line to near-line can be done manually. The jukebox appears on the network as just another drive letter, say h- or j-drive.
However, more typically, the whole process of what, when and where is undertaken as an automated process, with the network manager setting the rules and criteria. This is known as Hierarchical Storage Management or HSM.

At the bottom of the hierarchy is off-line. The equivalent of the company archive room in the basement. In the case of the jukebox, off-line is simply the removal of a magazine of discs and putting it on a shelf.