MySpace looks to USC to help servers keep up with users

How do you keep a potential half-billion social networkers current? A Viterbi School of Engineering expert tackles the growth problems of one of the world's largest computing systems

Imagine a moment - a thousandth of a second - in the life of a MySpace computer.

In that brief fraction of an eye blink, thousands of fingers on mice, spread across thousands of square miles, have clicked-in urgent requests for as many chunks of data: a photo needed in Minneapolis, video needed in Des Moines, a forum comment wanted by an observer in Detroit.

As the vast social networking system grows, each millisecond becomes more and more crowded with requests like these. Now, a University of Southern California specialist is working to make sure that the answers keep coming back quickly, even with tens of millions of new users.

"If MySpace were less successful," notes Shahram Ghandeharizadeh, a professor in the USC Viterbi School of Engineering's department of computer science, "there would be no problem. But at the current volume of transactions, getting to the data quickly becomes an issue. "

The key to speed and capacity is what is called DRAM. "Ideally," says Ghandeharizadeh, who is director of the USC Database Laboratory, "you want all the data requested to be in the quick-access cache memory of the servers, the DRAM, rather than having to retrieve it from the servers' disc memory, which is much slower."

But the total volume of data created by users is far more than the DRAM cache will hold. And as the user population grows at an accelerating pace, more and more requests arrive to query a larger and larger body of information. Even the innovative Berkeley DataBase system (BDB) that MySpace uses to keep interactions quick is coming under increasing strain.

BDB keeps MySpace information flowing by quadruple redundancy: each section of users is served not by one but by four overlapping servers that share DRAM space, making the system faster, more reliable, and more scalable.

"Now it works," says Felipe Cariño, who heads MySpace Research, the company's in-house R&D facility, "but if you double it, it may not." And he says the population may in fact double as people in China and other areas learn to meet and greet each other on their own sites.

Ghandeharizadeh is working with Cariño, a 1995 USC Marshall School Executive M.B.A., to find a way around the impending squeeze. Cariño dubs the effort the "Gemini Project," after the famous twins: "Two heads, Viterbi and MySpace, coming together."