CERN moves 2,200 accelerator control computers from CentOS to Debian over the x86-64-v2 baseline

Sources: primary, discussion
Summary: CERN is moving 2,200 accelerator control computers from CentOS to Debian. A compiler baseline of x86-64-v2 would have left 47 percent of those control systems unable to boot, and another 17 percent would have failed under x86-64-v3, close to 65 percent in total. CERN put the estimated total cost of upgrading the affected machines at 5.4 million Swiss francs, which covers engineers, technicians, added rack space, and possible excavation rather than hardware alone.
Why it matters: A distribution's microarchitecture baseline is a hardware retirement schedule for any fleet with long-lived embedded machines.