Nearline Storage
Disk based storage for data protection and data retention has become an established practice in data centres. However, the sheer amount of data required by today's applications can create management issues and consume valuable storage hardware resource. Therefore data centre managers must ensure that disk storage units used for their applications are structured in such a way to offer manageability, energy efficiencies and features such as data deduplication, that reduce the actual amount of disk capacity required.
Nearline storage is a term used in IT to describe data storage that sits between Primary storage, used for data that needs to be accessed quickly and frequently in a 24/7 environment, and offline storage, removable media such as tape. Nearline storage systems today are mainly based on inexpensive SATA disk RAID systems and can connect directly on the network (NAS), directly to the back up server (DAS) or into an existing storage network (SAN) via FC or iSCSI.
Why deploy Nearline storage
Moving data to Nearline storage allows for a reduction of database size on the primary storage system that results in improved speed of performance where it is most needed. Nearline storage can then be deployed to store less frequently used data and also allow fast back up of critical data that would need to be quickly restored in the event of data loss on the primary system. Once data is backed up to the Nearline system this can then be archived off to a removable media such as tape, however other technology such as SATA disk can be used. This method of data management is also known as 'Disk to disk to tape' back up (D2D2T).
Advantages of Nearline storage
Besides reducing the database size and traffic on the primary storage, it also enhances the speed and accessibility of companies back up files. Traditional issues with back up have always been related to the speed of tape devices and the window available to the IS manager. With many company’s now running 24/7 global businesses they no longer have any window to back up and require a real-time solutions to ensure they have solid data protection policies. By replicating primary storage to low cost SATA disk arrays data can be quickly backed up and stored online as a primary copy. It can then be archived to tape at a set time away from the network reducing the bottlenecks associated with backing up directly to tape across the network.
Local availability and serviceability of data are also a key requirement of businesses that have departments which are geographically distributed. Due to its low cost/GB and ease of installation using NAS or iSCSI, Nearline storage is a perfect solution to ensure remote data is stored securely and can be easily managed with little local storage or IS skills required. This then allows data to be backed up or replicate to a central location without overheads on their own network.
Summary
Nearline storage requirements are doubling year on year as more data is being kept for a variety of reasons from legal requirements within business to entertainment at home. It is this growth that is fuelling the adoption rate of low cost SATA based storage systems across a variety of host technologies such as NAS and iSCSI. As more data is created more will need to be archived and kept but also needs to be easily managed with the ability to access the data quickly.
