Back in 2004 or 2005 the company i was at had a few hpux systems on itanium running oracle. At one point we had a network loop for a few minutes. Fixed it but the out of band management controllers on the itaniums all hung. I believe they had redundant management controllers. Unable to reset them HP support advised to just pull them out and re insert. They were hot swappable. Those itaniums were not my responsibility. Fortunately the people tested it on a non critical system and the box crashed immediately.
That said several years later after I left the company's largest customer said they would pay to upgrade the infrastructure. But they had to get rid of the (then) red hat linux boxes running oracle and go to hpux or Solaris or something more solid. Not sure what the issues were but I recall my co workers who managed those systems were quite excited to be able to use linux with oracle (maybe RAC too I don't recall) before I left.
Same company after i left built active active datacenters. But their app stack sucked. At one random time I emailed an ops guy there and he said something along the lines of they were 4 or 5 hours into an outage on their 4 or 5 nines configuration. I had a good laugh