About Cisco WAAS File Services
Enterprises today have remote offices in different parts of the country and around the world, often with remote offices having their own file servers to store and manage the data needed by local users. This method of operation can be costly to purchase, manage, and upgrade file servers at each remote office, and to protect data in case of server failure. To achieve the required level of data assurance, the remote office must devote resources to back up the data at the remote site and physically move it to a secure location, often at a considerable distance from the site. When this scenario is multiplied by tens, hundreds, and thousands of remote offices, the enterprise data management costs can rise exponentially, along with the increased risks to critical data.
The logical solution is to move all of the enterprise’s important data to a central location containing the facilities, trained personnel, and storage mass required to manage the data properly. By having a data center provide backup and other storage-management facilities, the enterprise can achieve better utilization of both personnel and storage, as well as a higher level of data assurance and security.
However, the WAN between the enterprise’s data center and its remote offices can be unreliable and slow, with limited bandwidth and high latency. The WAN can also create other obstacles to the implementation of the data center solution, including file server protocols that operate over the WAN. Every file operation generates several exchanges of protocol messages between the client and the file server. While often not noticeable on the LAN, this can quickly cause high latency over the WAN, which sometimes can break the file server protocol altogether. Even when the file server protocol functions correctly over the WAN, there can be long delays between each transaction, which can cause timeouts in user applications such as word-processing programs, image-editing programs, and design tools, or which stop the applications from functioning correctly.
The problems of unreliable WANs, file system protocol compatibility, and user application compatibility diminish productivity, and overall, negatively affect the user experience.
Cisco WAAS File Services overcomes WAN latency and bandwidth limitations by caching data on Edge WAEs near the user. This data caching method allows branch office users to access centralized data at LAN-like speeds over the WAN. The solution is based on several key concepts:
Use the WAN as little as possible: By minimizing the number of operations that need to traverse the WAN, Cisco WAAS effectively shields users from many of the obstacles that WANs create.
Use the WAN optimally: Cisco WAAS File Services uses sophisticated caching, compression, and network optimization technologies, which enable the system to use the WAN optimally.
Preserve file system protocol semantics: Although Cisco WAAS software uses its own proprietary protocol over the WAN, it leaves intact the complete semantics of the standard file system protocol commands. This is essential to preserve the correctness and coherency of the data in the network.
Make the solution transparent to users: The best solutions are the ones that do their jobs unnoticed, without interfering with end users’ operations or forcing users to change their ways of doing business. The Cisco WAAS File Services solution does not require any software installations, either on the server side or at the client-side, and does not require a user to learn anything new. Users derive all the benefits of having a secure data center without needing to change any of their work habits.
By using Cisco WAAS File Services, enterprises can consolidate their file servers to a data center that provides the facilities, IT personnel, and storage devices required to manage the data properly.
The following figure shows a typical deployment scenario after Cisco WAAS File Services have been set up.