Manage Learn to apply best practices and optimize your operations.

Issues/benefits of offline, online and Nearline® storage

Graham Irving shares on some of the considerations involved in offline, nearline and online storage.

Graham Irving Managing Director, K-PAR Archiving Software

Graham Irving joined K-PAR Archiving Software, Ltd. in May 2000 as the managing director. He has over twenty years of experience in the optical storage industry. Irving holds a B.Sc. degree in Computer Science from the University of Calgary (1981), and has been a member of several boards and panels, including the American National Standards Organization Optical Disk Committees, X3B11 and X3B11.1.

Having a storage strategy in place saves money and solves the complexities of data management, says Graham Irving, Managing Director, K-PAR Archiving Software.

Every organization, without exception, needs to store information. However most organizations don't give sufficient consideration to how they store their data. Many organizations find data storage costly and complex, but more often than not, this is usually because they don't have a sufficient storage strategy in place which ensures that data is managed effectively and efficiently.

Successful data management is achieved by having a clear understanding of the importance data plays in the organization. The starting point for this is asking yourself, 'What is the true value of this data?' In other words, how vital is it to the successful running of the business? This will help focus organizations when formulating a data storage strategy.

Another consideration should be, 'How often is this data likely to be accessed?' Essentially, data storage can be broken down into three main categories:

  • Data which needs to be accessed on a daily basis
  • Data which is required regularly, but not frequently
  • Data which needs to be kept, but may never need to be accessed.

This is reflected in the online, Nearline®, offline approach.

Online storage

Online storage is important as it provides instant access to information across the network. However, too many organizations make the mistake of storing all of their information on their network servers, either on the computer's hard disk memory, or utilizing RAID (Redundant Array of Independent Disks) technology.

They believe that this provides them with instant access to the information, and, while this is true to a certain extent, it is a costly approach which can make the data vulnerable to being altered (either deliberately or accidentally) or even deleted. This is where assessing the value of the data held becomes important, because if the organization experiences any network downtime and cannot access its mission critical data, it is only a matter of time before the bottom line of the business is impacted. As the amount of data stored online increases, it puts the server and network under more pressure, and essentially slows down the operating speed and therefore efficiency of the system. Putting all your eggs in one basket with the objective of rapid data access often backfires. The sheer quantity of data will overload the system, become inefficient and ineffective.

Another, important issue pertaining to online storage is that the information held is not legally admissible. Information which is likely to be required for legal reasons must be held on a write once media such as CD-R, DVD-R or WORM. This means that the data held cannot be altered or become corrupt in any way. Deciding which data should be removed from the magnetic disk and only stored on tape backup is often too big a task for any company to handle. So what tends to happen is that IT managers just continue to buy more and more disk space and more and more tape to back it up. With a managed storage environment all data is stored near online and only becomes online when it is needed.

Nearline storage

Data that is complete and not required on an on-going basis, but is still likely to be accessed frequently, should be held Nearline, a registered trademark of Storage Technology Corporation. This way, access is quick and simple, but as the information doesn't actually sit on the server or the core IT network, it doesn't impact the wider IT infrastructure.

Nearline storage typically utilizes optical media such as CD, DVD or magneto optical which offers complete data integrity and has proven archival properties. The optical disks are held in jukeboxes and connected to the IT network using data management software, such as K-PAR's Archimedia software. The software effectively acts as an interface between the users and the storage media so that they can seamlessly access the information without even realizing that it is not directly held on the network.

Unlike online storage, data held on optical disk can utilize write once technology, which satisfies all legal admissibility requirements. Nearline storage is easily scaleable as additional jukebox capacity can be added without impacting the rest of the IT infrastructure.

Offline storage

As the near online storage area grows, the IT director has the choice of either adding more jukeboxes or removing the optical media out of the jukebox and still have the ability to manage the archive. When a user requests the data held on the disk, a message is sent to the systems administrator to insert the disk into the jukebox to make the data available or providing the user has the right permissions he could retrieve the disk and insert it into a standalone drive.

This means an organization is never out of storage space.

Back up

Organizations are well aware of the importance of having a backup of their data which can be called upon should the original information be destroyed in any way.

Backing up data is an essential part of every company's data storage strategy, but in reality, it is unlikely to need to be retrieved and accessed. Tape media is the most appropriate media for backup purposes as it is cost effective. This approach to data storage means that the reliance on tape backup is less important as the only data that needs to be backed up is that which is held on magnetic disk. Data that has been archived to optical media does not need to be backed up.


Information and data is integral to an organization's success, so it is essential to give sufficient thought to how it will be stored. A storage strategy that combines the three types of storage -- online, nearline, offline -- is the ideal solution. In this case, online would be magnetic disk (hard disk/ RAID) for frequently accessed documents, nearline would be optical technology using jukeboxes for archiving of all information, and offline is media held outside of the jukebox but managed as part of the overall archive and backup (tape for backing up purposes).

This ensures that the data management strategy runs inline with organizational requirements, making for a more cost saving and efficient business.

Dig Deeper on Data storage management