Kakao ran South Korea's messaging on one data center — a fire took the country offline

Kakao runs much of South Korea's daily life online. Its KakaoTalk messenger had 43 million monthly active users in a country of 51 million, and its Kakao Pay and Kakao T apps handled payments and taxi-hailing. Much of that ran through a single data center: an SK C&C facility in Pangyo, just south of Seoul, which it shared with rival Naver.

On the afternoon of 15 October 2022, a fire broke out at the SK C&C building. Power was cut for safety, and the fire took about eight hours to extinguish. KakaoTalk, Kakao Pay and Kakao T went down and stayed down for nearly a day, disrupting payments, online transactions and taxi-hailing across the country — affecting, as one report put it, nearly all sectors, even finance and transportation.

The fire was the trigger, but the outage was the architecture. Experts blamed Kakao for having no disaster-recovery plan or backup site for the country's biggest messenger; had it kept a hot site, they said, the disruption would have been resolved quickly. The proof was next door: Naver, in the same building, had an off-site backup and restored its services within hours. Kakao said it had not expected the power outage and that replicating so much data took time; it announced it was building its own data center in Ansan.

The contrast made the lesson unmistakable. Two companies in the same building, the same fire — and one was back in hours while the other was down for a day. The difference was a backup site one had invested in and the other had not. For a service a country depends on, redundancy is not an expense to defer; it is the price of being essential.