The Basics of Data Storage

By Meenu Gupta
Updated: December 11, 2013

The Basics of Data Storage

Network-based data storage is broadly termed as Network storage. But what are the varied technologies that constitute it? Why is it important to learn the basics of storage technology? Not only is storing data appropriately important, it is becoming increasingly indispensable as data privacy and legal matters become inexorably intertwined with business operations around data, as well as adding severe penalties for individuals and corporations for failing to comply.

The ever-evolving field of network storage is comprised of several technologies that include Direct Attached Storage (DAS), Network Attached Storage (NAS), Storage Area Network (SAN), Internet Small Computer System Interface (iSCSI), Redundant Array of Independent Disks (RAID) and cloud storage. It is, however, imperative for a company to understand its storage needs before making a choice. Considering that an average desktop user requires about 30 GB for data, 20 TB or more can be allocated for 1,000 users as an example.

Direct Attached Storage (DAS), as the name implies, is the storage device that is directly attached to its host system. For instance the internal hard drive of a server computer is a DAS. However storage devices that are in an external box are also DAS. Despite the new advances in data-storage, DAS is still, by far, one of the most common methods of storing data for computer systems.

For small and mid-sized businesses, Network-attached storage (NAS) is an ideal choice as it is fast, easy to use and reliable. On an average it costs about $200 for 300GB or more. It is easy to deploy too. A single hard drive with an Ethernet port or built-in Wi-Fi connectivity provides economical data storage that many clients can share in an IP networking environment. In case more storage is wanted, additional USB and FireWire ports  can be added to connect external hard drives.

In a NAS storage solution, multiple hard drives in a RAID (Redundant Array of Independent Disks) level 1 array may offer two or more hard drives in a single network-connected device. Files on the main drive are then automatically copied to the second drive providing a secure backup. NAS also consolidates storage and increases efficiency by helping in offloading file serving from other servers to the network. This allows I/O requests to overlap such that data is stored simultaneously on multiple hard disks whether for backup purposes or to provide better performance. The main objective of data protection is attained by RAID by the following features: mirroring data between sets of drives, striping data across drives, mirroring striped sets and rebuilding disks with parity data.

In a storage-area network (SAN) many storage devices are interconnected to each other as well as to one or many servers. Using special switches as connectivity points, that look a lot like normal Ethernet networking switches, SAN connects devices. SAN is a high-speed network that supports disk mirroring, data backup and migration. One of the key technologies that is rapidly developing the SAN market is Ethernet protocol Internet Small Computer System Interface (iSCSI). iSCSI facilitates data transfers over intranets by carrying commands over Internet Protocol (IP) networks. It also manages data storage and retrieval in long distance local area networks (LANs), wide area networks (WANs) without depending on the location of the data. Fibre Channel is another network protocol that is used for SAN.

Local area networks (LAN) may serve well in a home network or in a company or FDDI network. The multiple computer users share a common communications link. A wireless LAN is preferable and a cheaper option than wired LAN. Companies may  chose from ethernet, token ring or FDDI LAN technology.

For data that is accessed frequently, primary storage may be used. It consists of the most expensive storage tiers. Data can also be classified and stored on basis of how frequently it is accessed, performance needs and the levels of protection. Tiered storage technology comes in handy in such a scenario as it allocates the types of data to different storage systems, thus enhancing overall efficiency. For instance, recently accessed critical data can be stored in tier 1 data, the highest performance drives available, while the less used and less crucial data is stored in tier 2 data on less expensive hardware.

Cloud storage, a growing trend among business data storage, is increasing in popularity for several reasons. The prime reasons are data accessibility and to some extent data security, as the data is stored in a remote database via the internet. It allows data to be shared safely and easily with other business partners and there is no need to manage a physical storage device. However, remote storage requires higher speed network access, especially for larger files. Online file storage is easy to use as well as economical.

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