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Server Attached Storage
Server Attached Storage, also referred to as Direct Attached Storage (DAS), entails the attachment of storage disk arrays directly to general-purpose servers. Under this architecture, users submit I/O requests directly to the disk controller residing on the server to which a user is connected.
With minimal storage needs, server-attached storage is typically more effective for smaller enterprises. However, for rapidly growing and large enterprises, the architecture of server-attached storage environments may be problematic. Server-attached storage often exacerbates IT problems, though the addition of storage to existing servers in the network may seem logical. As enterprises continue to invest in server attached storage, information becomes increasingly distributed across the enterprise and isolated from users not directly attached to the storage device. Thus, the installation and maintenance requirements of server-attached storage compound these problems.
Though DAS offers a simple way to add needed storage, administrators must continually add storage arrays and work to maintain a complex, distributed network. This often causes more problems than they are solving. As a result, enterprises run the risk of heightened TCO due to increased IT expenditures in administration, overhead, and decreased user productivity.
Server Attached Storage versus NAS
NAS also offers enterprises several other advantages over server-attached storage. NAS not only provides network simplification but ample storage capacity as well. As previously mentioned, the installation and maintenance of server-attached storage solutions can be time consuming and require network downtime. Alternatively, NAS only requires a few minutes of downtime during maintenance and upgrade, and users retain the ability to access file services on the appliance. NAS solutions offer large enterprises the capacity they need in one device and small enterprises the room to grow.
Furthermore, with a NAS solution, enterprise information resources can be consolidated onto one system. In addition, by streamlining network architecture with NAS, storage and file resources are shared by the entire enterprise, and administrators need only be concerned with maintaining one system. Among other advantages, this results in simplified system backups. Why? Because with NAS, only one server must be backed up, rather than multiple, dispersed server-attached storage arrays. In short, with a NAS solution, enterprises effectively increase user productivity and lower TCO.
The Server Attached Storage strategy causes enterprise resources to become more distributed and network maintenance more difficult. Users in a server-attached storage environment experience sluggish performance, suffer from unavoidable system downtime, and are typically incapable of sharing files across operating systems. As an alternative, NAS supplies enterprises with:
- Centralization of resources and management,
- Enhanced performance,
- Increased system uptime,
- Necessary storage capacity, and
- The ability to share files transparently across the enterprise.