The appearance of network-attached storage (NAS) enables many homes and small to medium businesses to adopt economic method of storage equipment comparing with storage area network (SAN). The NAS provides a frame of file management that the homes and businesses can experience the complete and secure application. According to the cases that the writer noted, numbers of enterprises also place a NAS in a box to work as a back-up server and set up another NAS collocation internally to have double security of the data.
There are several elements for enterprises to evaluate purchasing a NAS which will also be the future trends.
Storage Capacity
A 2-Bay NAS server equipped with 2 500GB HDs / 1TB HD is a common choice for a small-size business when 4-Bay, 5-Bay or 8-Bay servers are more suitable for larger businesses.
RAID Array Systems
A hard drive is a hardware component of limited life span. When a hard drive failure occurred, the data stored is not easy to get restored. At this moment, the hard drive array system plays an important role. Many small-size businesses use 2-Bay NAS with 2 hard drives which follow the RAID I model for the mirroring. When one hard drive is down, the other can back up to replace the original one when medium-size businesses usually go for RAID 0, RAID 1, RAID 5, RAID 5 + Spare Disk (RAID 6) and JBOD for more options.
Bandwidth
A NAS can be as good as a data storage computer differentiated by CPU and RAM. The spec is determined by the processing time and bandwidth of the NAS. The bandwidth of an entry level NAS with Giga Lan can reach 10MB per minute as high-end models can reach 35MB to 50MB per minute.
Networking Integration
High-end Enterprise NAS usually adopt two networking interfaces to separate the loading of network and data storage that can balance the efficiency in a large-scale network infrastructure.
iSCSI application and integration
iSCSI devices offer major benefits to rugged and industrial environments by ensuring the reliable storage of mission critical information while reducing costs and maximizing resources. A filing system is usually File Level storage to store the data but using storing level functions. Some servers like a SQL serve are not able to load the file in shared directories. When iSCSI is a Blocking Level Storage which makes sure that all data can be accessed with reasonable performance by directing the storage block addresses where the data is going to be placed so that iSCSI can be operated in local server and the SQL server can easily access the data/files. It is a method of high efficiency and cost effectiveness.
Future Development
Even the NAS has been a mature product in business, the demand of larger and larger storage capacity and access to the digital data through wire or wireless for consumers, NAS is also ready for end user market. The growth will be explosive and it is expected that NAS will become the next generation media gateway.
According to most of enterprises with which the writer has spoken, the average spending of data storage equipment is accounted for 5% of IT budget. If adoption of SAN, the expending might exceed 50% of IT budget. The cost difference between NAS and SAN is apparent. For cluster system, the cost of an iSCSI NAS is also more reasonable than a FC SAN that can save a great purchasing cost.
Flowing with this trend, big-size businesses might still use FC SAN in crucial data storage areas and NAS for sub area in the future. The combination can ensure the security and reliability and cost effectiveness as well. The small-medium businesses might not be able to afford SAN system cost hundred thousands but use high C/P NAS in their data storage systems. The high-end NAS also support iSCSI that can expand the application of NAS. The percentage of NAS for home users is not obvious at this stage but the writer believes the usage of NAS for home users will be more in the future. When Windows VISTA and Windows Server 2003 and above all support iSCSI as a complimentary tool, iSCSI will become the main stream. In terms of manufacturers, Taiwan-based D-Link, Synology, Promise, QNAP Systems all introduced powerful and reliable NAS equipments. It is worthy believing, the popularity of NAS in enterprises is visible. Besides coping with the iSCSI technology, the iSCSI Initiator was embedded in Windows Vista which was introduced in 2007 by Microsoft that saves extra time to download. The Windows server 2008 also did the same thing. Jade Quantum Technologies, a Taiwan-based iSCSI manufacturer, shares a good chance in growing in this area.