Power shortages remains the biggest problem. The government has reactivated hydro and fossil fuel plants, but starting July 1 all facilities that consume more than 500kWh are ordered to reduce their peak power usage by 15 percent from a year earlier.
Data centers operators have fought the cap with some success. They argued their facilities are critical infrastructure and that many had already slashed their consumption before the earthquake as part of energy-efficiency projects. Also, companies have been "evacuating" servers and storage from Tokyo offices to their data centers because of power shortages in the capital, making it even harder to reduce demand, Yamanaka said.
"We told the government it was physically impossible" to meet the reduction targets, he said. The government eventually backed down and has reduced the target for data centers to between zero and 15 percent, depending on how much they reduced energy use the year before. Fines for noncompliance are high -- the equivalent of $12,500 for each hour over the limit.
Power problems are likely to worsen this summer when cooling systems work overtime, and could lead to further rolling blackouts.
Despite the preparedness, lessons were learned and companies are updating their disaster recovery plans. Communications was affected more than expected, and while social networking tools were a substitute for phone lines, they were also a place where rumors spread fast, Yamanaka said.
Many customers sent staff to their collocation providers' data centers to check on damage. They often got stranded due to transport failures, and blankets and food were in short supply. Service providers must find ways to communicate better with customers when disasters strike, he said.
Data centers are also trying to find ways to cope with long-term power shortages and the price hikes that result, and how to replenish their fuel supplies more quickly. Service providers may alter contracts so that customers shoulder some of the increased cost for raised energy prices.
JDCC is compiling a more detailed report on the quake and wants to share it with operators overseas, Yamanaka said.
The talk was particularly resonant for data center operators based in areas susceptible to natural disasters. David Smith, a principal with Ecom Engineering in Sacramento, California, said he found the talk "fascinating," and that he had expected data centers to be more affected by the earthquake.
Preparedness is a big part of the solution.
"Because we live in Japan we have regular drills for earthquakes and also fires, and most data centers have self-fire fighting organizations that help each other," Yamanaka said.
"Before kids learn how to read and how to count numbers, we get educated with those earthquake drills."