Windows Media Server Specifications

The Windows Media server farm will be added to a rack in the area with the other intranet Web servers and devices. A cluster of three servers will handle all streaming media. The IT department decides to purchase computers that will be able to handle the projected load over the next two years. Utilization of these computers should not exceed 50 percent of CPUs, hard drives, and network resources.

Fabrikam purchases computers with dual processors running at 2 GHz. The computers will originally have 512 MB of RAM, upgradeable to 1 GB, and bus speeds of 400 MHz. When hosting streaming media content, RAM, hard drive capacity and speed, and internal bus speed are very important.

The servers contain five hot-swap hard drive bays. The IT department will use two 18 GB drives for storing the operating system, back-up files, and applications. The remaining slots will contain 36 GB drives and be used for storing Windows Media files and other content. In the future they will switch over to a RAID disk array system to provide fault tolerance. The Network Load Balancing (NLB) service provides one level of failure protection. However, hard drives have the highest failure rate in a streaming media server system, and a RAID 5 array would reduce the cost of drive replacement. In this case, however, Fabrikam decides to use the drives built into the server.

If possible, digital media content should be kept on a separate drive from the one used for the operating system. Hosting streaming media content is very different from a server perspective than hosting Web pages, images, and other static data. When a Web page is sent, for example, the hard drive is accessed for a second or two while the data is read into a memory buffer and sent to the client. One hard drive can serve many Web pages and images concurrently because data access times are comparatively short.

When streaming digital media content, on the other hand, data must be sent continuously. A storage system must be able to handle multiple concurrent streams for much longer periods of time, and this places a heavy demand on hard drives. By using separate drives for the operating system and applications, the content drives do not have the additional burden of storing and retrieving system data. Newer systems with bus speeds of 400 MHz or higher can help move the data quickly from the drives into memory. To decrease the load on the hard drives and the system bus, large amounts of RAM are helpful for storing and sending data.

Besides the removable hard drives, the only other hardware needed is three NICs: one 1000BT NIC for streaming content to users, one 100BT NIC for administrative use, and one 100BT NIC for content management.

In this configuration, the Fabrikam staff have plenty of room to expand as demand increases. 100 GB of content storage should be sufficient for now, considering it could hold over 2,400 hours of content streaming at 100 Kbps. Larger drives (or an external disk array) can be added to the computers, if needed. It is far more likely that network bandwidth will be saturated before the load on the servers becomes a problem.

RAM can be added if memory utilization is high. The CPU speed should not be an issue. If demand increases to a point where the CPU usage is above 50 percent and additional RAM does not help, more servers can be added to the media server farm. A Windows Media deployment can scale both vertically (by increasing host resources, such as CPU speed and RAM), and horizontally (by increasing the number of servers). If Windows Media server resources are increased, network bandwidth should also be increased to handle more concurrent streams. If network bandwidth becomes an issue, the IT department can also investigate adding cache/proxy servers throughout the main office to spread out the load on the Toronto network.