Kyoto University December 2021 — buggy backup script deleted 77 TB across 14 research groups

In December 2021, a routine software update at Kyoto University's supercomputing center (IIMC) interacted badly with the center's backup scripts and deleted approximately 77 terabytes of research data across 34 million files belonging to 14 research groups. The buggy update executed December 14-16, 2021. Approximately 28 TB across 25 million files belonging to four of the fourteen groups was the only copy the center held; that fraction is permanently lost (S-0029).

The case is the cleanest available demonstration of C-0018: the backup script and the data it was meant to protect executed in the same software context. A single administrative action (the buggy script update) reached both. There was no protection because the architecture did not provide an independent failure domain between the primary copy and the backup.

The institutional response (post-incident apology, process change, software auditing) addresses the proximate cause but not the architectural property that made the proximate cause catastrophic. A backup that shares a software failure domain with the data is not a backup; the cure is independence at the protocol layer (M-0002), not better software auditing.