Why Valentine’s Day needs data centers

It’s a happy Valentine’s Day if you’ve found a match on an online dating site. But it could be a tough day for IT people at Match, eHarmony, OKCupid and other sites, which might face traffic booms as antsy users scramble to find last-minute dates.

There’s certainly plenty of demand for the services. In 2009, CIO reported that more than 40 million Americans had tried online dating. In September 2012, 1 in 10 internet users frequented an online dating site, according to a December 2012 report from comScore.

Sites vary as to the times of year when traffic peaks. The number of unique visitors to eHarmony.com increases 45 percent on Valentine’s Day, and the boost continues until the end of the month, a spokeswoman wrote in an email.

The biggest day of the year for Match.com registrations isn’t Feb. 14; it’s actually Jan. 2. “Then we get another big spike after the Valentine’s Day holiday, so this weekend will be another spike,” a spokeswoman said. And for Zoosk.com, the peak comes on Dec. 26, while traffic is consistently heaviest in January.

How do engineers accommodate all the traffic and not sacrifice performance?

For eHarmony, it was a matter of scaling out infrastructure. “The systems over the years have been expanded to absorb large spikes to all the main areas and events on the site, such as posting photos, communication requests and the interactions with the mobile apps,” the company spokeswoman wrote.

Computerworld reported in 2009 that eHarmony had 4 terabytes of user information in storage for 20 million users. That comes from responses to the site’s Relationship Questionnaire. The spokeswoman did not immediately have current figures available.

Match.com was storing 70 terabytes of user data for more than 1 million subscribers when Microsoft (s msft) published a case study on the dating service last March. Until May 2010, Match.com was updating user information on 110 Microsoft SQL Server servers across two data centers in the United States. In order to keep profile updates timely — less than two seconds — the company began distributing the updates across the servers, rather than update the entire dataset at once.

Valentine’s Day isn’t necessarily the high point of the year for Facebook. (s fb) Jay Parikh, Facebook’s vice president of infrastructure engineering, cited Halloween as one of the highest times of year for photo uploading, as my colleague Stacey Higginbotham reported. When Facebook demand spikes, servers stocked with flash memory in the data center instead of hard disk drives and tapes ensure consistently high performance with a wide variety of data — and there’s plenty of room for storage, too. Facebook’s flash-only database servers, codenamed Dragonstone, feature 3.2 terabyte flash memory cards from Fusion-io. (s fio) Flash memory might come in handy at dating sites’ data centers, too — the Dragonstone flash memory became part of the Open Compute Project last month.

Feature image courtesy of Shutterstock user 3Dstock.