not a novelty. the true bigiron vendors (not sun) had been doing this for decades.
mainframe reliability puts the upstart unix systems to shame.
this is actually so ancient it’s hard to find docs. here’s something from 1976. (the report is 1990 but the hardwares dates to ‘76). https://www.hpl.hp.com/techreports/tandem/TR-90.5.pdf