Ten Things You Should Know About Document Storage

Documents have to be stored not only during their current periods but for years thereafter (forever in some cases). Statutory and litigation requirements and preservation of history, for example, make such storage necessary. Storing documents needs storage media, which costs money. Hence it is important to optimize document storage by removing unwanted documents at the earliest time and avoiding redundancy of documents.

1. Government regulations stipulate that different kinds of documents be preserved for specified periods, such as seven years. Litigation possibility requires that documents that might be needed as evidence in a lawsuit be preserved as long as there is a remote possibility that a lawsuit might be filed. For these and other reasons, document storage for long periods should be understood as unavoidable.

2. Documents are stored on storage devices ranging from paper and filing cabinets to microfilm, magnetic tape, hard disks, CD/DVD and solid state devices like flash drives. The media differ in terms of costs, durability of stored data, ease of handling and portability.

3. Storage can be primary as when data is stored on on-line hard disks and can be accessed in milliseconds by the system. It can be stored on less expensive secondary near-line media such as robotic devices that retrieve and mount needed media as called for by the system in seconds. Data can also be stored on least cost (and safer) off-line in removable media as backup or archive, to be accessed infrequently if necessary.

4. On-line storage is necessary for frequently used current data. If too much data is stored on-line, it can affect system performance, slowing it down. Hence it is a good practice to remove infrequently used data to secondary or off-line media.

5. Secondary storage media are near-line in that the data can be made accessible in seconds. The data is stored on removable media that are stacked in a device with robotic arms. On receiving a system command, the arm will retrieve a selected media and mount it on an on-line drive. This operation is typically performed in seconds so that there is no appreciable delay in accessing the data in secondary storage.

6. Data is stored off-line on removable media not only because they are used infrequently but also because the media can be stored away in less expensive and safer premises. For example, backups of data will be needed only if the primary data is lost and can be stored in separate premises so that events like a fire at the primary location do not affect the backup.

7. It is a common practice to monitor the access rates to different types of on-line data and move the infrequently accessed types to near-line storage. This can be done automatically and can optimize system performance.

8. The media stored in the near-line storage devices are catalogued so that the system knows where each piece of data resides and can command the robotic arm to retrieve just the right disk and mount it on-line, when the need arises.

9. Offline storage protects data from the risks to which on-line data are exposed to, such as virus and hacker attacks, power fluctuations and system crashes. Remote storage of off-line data can even protect it from natural disasters like fire, flood and earthquakes that might affect data stored on the primary locations.

10. Electronic data can suffer from readability problems if they are stored long in the same format. File formats, storage media devices and software applications can all go through major changes as Information Technology changes. This can render old data unreadable. One solution to this problem is to transfer the old data to new format media on a regular basis.

Data that are needed for current processing needs are stored on on-line storage media such as hard disks and RAID systems. Data that might be needed only infrequently can be stored on near-line robotic devices with the ability to make them accessible in seconds. Backup and archival data are typically stored on off-line media that can also be stored remotely to keep them away from dangers like a fire at the primary location.