Documents must be stored not only during their current periods but for several years thereafter forever in some cases. Statutory and legal requirements and preservation of history for example make such storage necessary. Storing documents requires storage media which costs money. Therefore it is important to optimize document storage by removing unwanted documents as early as possible and avoiding redundancy of documents.
Government regulations stipulate that different types of documents are preserved for specified periods for example seven years. Costs require that documents that may be required as evidence in a trial be retained as long as there is little opportunity for a trial to be filed. For these and other reasons document storage for long periods should be understood as inevitable.
Documents are stored on storage devices ranging from paper and file cabinets to microfilms magnetic tapes hard disks CD DVD and solid state devices like flash drives. The media differ in terms of costs data storage durability ease of handling and portability.
Storage can be primary as when data is stored on on line hard drives and can be reached in milliseconds of the system. It can be stored on cheaper secondary immediate media such as robotic devices that download and mount required media required by the system in seconds. Data can also be stored at least cost and safer off line in removable media as backup or archive to access rarely if needed.
Online storage is necessary for frequently used current data. If too much data is stored online it may affect system performance and slow it down. Therefore it is a good practice to remove rarely used data for secondary or offline media.
Secondary storage media is close to each other as data can be made available in a few seconds. Data is stored on removable media stacked in a device with robot arms. Upon receipt of a system command the arm will retrieve a selected media and mount it on an on line device. This operation is typically performed in a few seconds so that there is no noticeable delay in accessing data in secondary storage.
Data is stored offline on removable media not only because they are rarely used but also for the media to be stored in cheaper and safer premises. For example backup of data is required only if primary data is lost and can be stored in separate premises so that events such as a fire on the primary site do not affect the backup.
It is a common practice to monitor access speeds to different types of on line data and move the rare access types to close storage. This can happen automatically and can optimize system performance.
The media stored in the nearest storage devices are cataloged so that the system knows where each data exists and can control the robots arm to retrieve the correct disk and mount it online when the need arises.
Offline storage protects data from the risks exposed to online data such as viruses and hacker attacks power fluctuations and system crashes. Remote storage of offline data can also protect it from natural disasters such as fire flooding and earthquakes that may affect data stored in the primary locations.
Electronic data may suffer from readability issues if stored for a long time in the same format. File formats storage media devices and software can all go through major changes when information technology changes. This can make old data unreadable. A solution to this problem is to regularly transfer the old data to new format media.
Data needed for current processing needs is saved on storage media such as hard disks and RAID systems. Data that may be needed only rarely can be stored on nearby robots with the ability to make them available in a few seconds. Backup and archive data is usually stored on offline media that can also be stored remotely to keep them away from dangers like a fire at the primary location.