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Data centreJapanEIR-2358

Fujitsu data centre UPS failure cuts power to banks and cloud servers

June 2012Published 13 Oct 2026Responsible editor: Chief Editor

SignificantElectricalProvisionalNext update 13 Oct
Estimated damageModelled by the register's adjusterHow? Know the real figure?
Figure hidden: shown to subscribersLow confidence
out of service for about •• daysShown in the record →Full estimate

Companies named in this entry: Fujitsu

What happened

On 7 June 2012 systems hosted at Fujitsu's Tatebayashi System Center in Japan stopped for long periods. All Tokyo Star Bank ATMs, some Resona Bank ATMs, all Sony Bank systems, some Nifty Cloud servers and Square Enix online games were affected. According to a Nifty Cloud report, cited by ScanNetSecurity, the failure of the centre's uninterruptible power supply (UPS) left about 7 per cent of servers without power. The centre had layered protection: a redundant UPS was to take over when a UPS failed, and if all UPS units stopped, power was to be supplied directly, bypassing the UPS.

The source says none of these measures worked. Nifty reported that the outage began at 5:59 and that a power supply unit in a data centre had failed. Nifty Cloud was provisionally restored at 19:40 the same day.

Contributing factors

The source says the redundant UPS and the direct bypass supply did not take over as designed. Further detail on why the layered protection failed was not available in the text reviewed.

Lessons learned

  1. Test automatic transfer to redundant UPS units and bypass supplies under real load, not only on paper.
  2. Verify that the failure of one UPS cannot disable the protection layers behind it.
  3. Map which customer systems share a single power domain, so that a partial power loss does not cascade into essential financial services.

More lessons on outages, backup supply and restoration, electrical protection and isolation, from every incident on the register.

Source

scan.netsecurity.ne.jp

Published 2026-10-13. Written from public reporting. Descriptive, not investigative. See the data accuracy disclaimer.

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Chart to reuse with this story: Data centre incidents in Japan, by year, free with a credit (PNG).

Data centre incidents in Japan: 8 entries, with a free alert for the next one.

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