Video storage
May 1, 2007 12:00 PM, BY BRAD GILMER
DAS, NAS and SAN offer distinct workfl ow benefits.
Network attached storage
NAS uses the same network for storage data access and other network tasks. The NAS is a dedicated server connected to an Ethernet network. (See Figure 3.) It appears as network drives to a local computer.
Figure 3. NAS servers attach directly to the Ethernet network used by workstations. The storage on the servers is advertised to the operating systems of the workstations in whatever way those operating systems expect to see remote storage, whether they are Mac, Windows, Linux or some other type of operating system.
The cost of NAS solutions can range from extremely low to very high, depending on the capabilities of the system. In some cases, NAS systems are easy to install.
Manufacturers have spent a lot of time and effort making them interface with just about any computer system. Furthermore, most systems behave like chameleons, making themselves look like native storage to whatever OS is interfacing to them. Inside, the system treats the data in a uniform manner, but at the interface points, the NAS presents the storage data and command interface in a way that the accessing OS understands. These capabilities are even available in low-cost units.
NAS is file-based, so it may suffer a performance hit compared with a SAN's block-based storage system. NAS' performance, however, will be better than DAS' because the server is a dedicated device and does not perform workstation tasks.
NAS solutions can be as unreliable as DAS or as reliable as SAN, depending on the design of the storage media and components. If a single disk is used and that disk fails, a user will lose all of the data. On the other hand, if a user invests in a NAS with RAID disks and multiple controllers, redundancy can be much higher.
Brad Gilmer is president of Gilmer & Associates, executive director of the Advanced Media Workflow Association and executive director of the Video Services Forum.
Comparing storage
|
| DAS | SAN | NAS |
|---|---|---|---|
| Cost | Low | High | Moderate |
| Complexity | Low | High | Low to moderate |
| Performance | Low | High | Moderate |
| Flexibility | Low | High | Highest |
| Reliability | Low | Highest | Low to high |
| Multiuser access | Low | High | Moderate |
| Access type | File | Block | File |
Send questions and comments to: brad.gilmer@penton.com
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