> So the leading hypothesis seems to be that perhaps the SSDs were from the same manufacturing batch and shared some defect.
Really sorry that you had to learn the hard way, but this is unfortunately common knowledge :/ Way back (2004) when I was shadowing-eventually-replacing a mentor that handled infrastructure for a major institution, he gave me a rule I took to heart from then forward: Always diversify. Diversify across manufacturer, diversify across make/model, hell, if it's super important, diversify across _technology stacks_ if you can.
It was policy within our (infrastructure) group that /any/ new server or service must be build-able from at least 2 different sources of components before going live, and for mission critical things, 3 is better. Anything "production" had to be multihomed if it connects to the internet.
Need to build a new storage server service? Get a Supermicro board _and_ a Tyan (or buy an assortment of Dell & IBM), then populate both with an assortment of drives picked randomly across 3 manufacturers, with purchases spread out across time (we used 3months) as well as resellers. Any RAID array with more than 4 drives had to include a hot spare. For even more peace of mind, add a crappy desktop PC with a ton of huge external drives and periodically sync to that.
He also taught me that it's not done until you do a few live "disaster tests" (yanking drives out of fully powered up servers, during heavy IO. Brutally ripping power cables out, quickly plugging it back in, then yanking it out again once you hear the machine doing something, then plug back in...), without giving anyone advance notice. Then, and only then, is a service "done".
I thought "Wow, $MENTOR is really into overkill!!" at the time, but he was right.
I credit his "rules for building infrastructure" for having a zero loss track record when it comes to infra I maintain, my whole life.