Case5 ESPN

1. How many requests from users does ESPN receive each second? Do you think this is a consistent pattern or does it have peaks and valleys? When does it peak?
ESPN receives 10,000 requests per second, however, I do not think this is a consistent pattern. I would say ESPN gets the most requests whenever there are big sport events and/or news. For example, NFL Sundays where there are multiple games at the same time, fans use the ESPN platforms to keep up with the scores and stats of the different games. The weeks before the Superbowl could be a good example as well. The valleys would occur when there are no sports events.
2. Why does ESPN store personal information and preferences on its databases and how does this personal information complicate the ability of ESPN to respond to requests from users? Why can’t ESPN just use Web page caching to handle the loads?
ESPN stores the preferences and personal information from users because of its personalization features. Every time a user sings into ESPN.com, the preferences for that user will load on the home page. If the user is a baseball fan then ESPN will show MLB content. This suppose a challenge for ESPN because the server has to respond different to every user and needs to handle much more data. ESPN cannot just use web catching because they have over 10 million users, every user with a different personalization, and they need to handle over 200 gigabytes of information.
3. How much information on users does ESPN store? Why does this pose a challenge for ESPN? Can’t they just use a standard 1 terabyte hard drive from a PC? Why can’t they use a single PC?
With full redundancy, ESPN needs to handle or store 200 gigabytes. This pose a challenge for ESPN because they need to store so much data that will not fit in a single PC, or two, or even a hundred.
4. What platforms do ESPN customers use when accessing their Web sites, and how does this further complicate ESPN’s processing picture?
Users use PCs and mobile devices to access the different ESPN websites. Users also use soccernet.com and espndeportes.com to access to ESPN content. This pose a challenge because ESPN needs to leverage the same personalization system for their mobile websites, soccernet.com, and espndeportes.com.
5. What are the key components in ESPN’s solution? Describe the function of each.
ESPN uses the Personalization DB, which consist of two components: The Grid, and the Composer.
The Grid uses IBM WebSphere eXtreme. It is an in-memory representation of everything in the Personalization DB. The Grid is extremely fast, it works at sub-millisecond respond time.
The Composer deals with the existing services. The users gather at the Composer, then the composer goes to the Grid and gets the users preferences. Because of the user preferences, the Composer know to what server go to request information.
6. Why is scalability so important to ESPN?
Scalability is important because ESPN can adapt the amount of servers they use to their needs. If they under estimate they can jump from ten to twenty servers right away. On the contrary, if they only need five of the ten servers they can drop the servers they do not need at run time.