Leading personalized internet radio station uses ioMemory to expand frequently-accessed cache capacity without scaling system cost and complexity. 

The Challenge

Pandora is personalized radio, combining the attributes of “original” radio and magnifying them with a combination of proprietary personalization technology and Internet technology—enabling a level of personalization and discovery for each and every individual. Pandora is available everywhere consumers are via a variety of connected devices, such as computers, mobile phones, tablets, automobiles, and TVs. Pandora currently accounts for more than 69 percent of Internet radio listening in the U.S. today.

Pandora maintains a large caching farm for frequently accessed content to ensure its customers the seamless listening experience they have come to expect. Aaron Porter, Pandora’s Director of System Administration, described the challenge Pandora’s growing popularity presented this caching tier: “Quality audio delivery to our many listeners is a major part of our production operation. In order to provide the best listening experience to our more than 125 million registered users, we needed a solution that offered greater scalability and reliability.”

As part of an innovative company that’s changed the way many listen to radio, Aaron and his team were confident they could find a solution that could,

1. Ensure the high performance its users had come to expect
2. Slow server scale-out
3. Improve hard-disk utilization
4. Reduce maintenance overhead

The Solution

After Aaron heard about Fusion-io through product reviews in the press and by talking to peers, he decided to give the ioDrives a try. Aaron and his team were impressed with the results.

More Cache to Support More music lovers

In the world of caching, size matters. Pandora had been investing in servers loaded with RAM to ensure a quality user experience. Aaron found that ioMemory proved a better alternative without compromising quality.

“The ioDrives perform as well as our RAM caches, but offer 10 times the capacity per server,” Aaron said. “Our total frequently-accessed music cache now holds 10 times the songs it used to, which both enhances existing user experience and gives us plenty of headroom for future growth.”

Aaron noted how ioDrive performance would slow its content delivery system’s scale out. “We currently assign each ioDrive-based server at least five times the load of our SAS-based hosts. As we continue our rollout, we see no reason why we shouldn’t be able to get to seven or eight times the workload.”

Going Green without compromise

In addition to improving cache performance and positioning Pandora for growth, the Fusion Powered system also allowed Pandora to cut costs in many areas.

Aaron said, “The Fusion Powered servers provide cache with order-of-magnitude higher capacities of NAND flash instead of RAM. This allows us to continue to support our growing listener usage on fewer, smaller, and less power-hungry servers. “

In fact, the Fusion Powered servers delivered 1.28TB of ioMemory cache per server, allowing Pandora to reduce per-server RAM needs.

Aaron also told us that using the Fusion Powered cache allowed Pandora to reduce its server footprint by about 40 percent—a move that resulted in an instant ROI on repurposed servers, lowered the content system’s power and cooling costs, and reduced maintenance overhead.

Aaron explained how moving data from hard disks to ioDrives resulted in a more efficient and overall cost-effective system: “We now store all the most frequently requested songs from our music archive on ioDrives. We have stopped purchasing SAS spindles for content delivery, which has extended the usable life of our disk-based systems by months, if not years,” Aaron said. “In the first quarter that we’ve run them, the ioDrives allowed us to delay purchasing 50 disk-based content servers—at least 1,000 SAS spindles.”

Expert Solutions Support for a Simpler, Lower-Maintenance System

When asked about implementation, Aaron noted the benefit that the Fusion-io team’s industry expertise provided. “It was immediately obvious that Fusion-io had an understanding of our technology needs and were willing to work with us to put together a solution that met our particular environment’s needs.”

The Fusion-io team worked with Pandora’s VAR to design and test the servers for physical layout and airflow. Pandora then worked directly with Fusion-io support to determine the appropriate ioDrive formatting. Aaron’s team was also pleased with the reduced number of possible disk failures with the new system.

System Overview

Before

• Custom-assembled Opteron-based servers,128GB RAM
• OS: Debian Linux
• Hard disks: 2 x 600GB 15k RPM SAS disks

Changes to System

• Custom-assembled Opteron-based servers, 32GB RAM
• OS: Debian Linux
• Hard disks: 2 x 500GB 7.2K RPM SATA disks (not used for data)
• Consolidated servers by about 40%

Summary

Implementing ioMemory gave Pandora the following benefits:

• 10x more cache per server to enhance user experience
• 10x larger overall cache to support future growth
• 7 to 8x workload capability per server slows scale out spending
• Replaces larger, RAM-heavy servers with smaller, more power-efficient servers
• 40% smaller server footprint
• Eliminates hard disks for frequently-accessed content to greatly extend life of existing disk infrastructure and defer expensive disk upgrades
• Open system and expert Fusion-io staff assists with designing optimal system with existing VARs and hardware partners

About the Customer

Pandora gives people music they love anytime, anywhere, through connected devices. (OK, we've added comedy as well so we're also up for playing some jokes you'll love.) Personalized stations launch instantly with the input of a single "seed" ­ a favorite artist, song or genre. The Music Genome Project®, a deeply detailed, hand-built musical taxonomy, powers Pandora's personalization ­ using musicological "DNA" and constant listener feedback to craft personalized stations from a growing collection of hundreds of thousands of recordings. Tens of millions of people in the United States turn on Pandora to hear music they love.