Re: Electrical Engineers To The Rescue !
Deary me ... I trust we're not all assuming the transaction that matters is at the storage interface. It's one piece of a much bigger puzzle.
It's a sad fact that the majority of organisations don't have a complete view of where their "business" transactions actually take place, and by inference what must be persisted, and how, given various types of failures.
Don't we have to fix that, before we trumpet to the business "replicate the array and we're all good, buddy"?
Try bringing up 46 Windows VMs from a corrupt VMFS v5 partition on a 1TB LUN. Ain't happening. Even if they booted, and NTFS found MOST of the orphaned clusters on the vdisks, the apps are unlikely to be consistent especially if they use a binary DB of some description. But blindly we continue to trust ... "she's up - must be good".
Putting too much money into a single link in the technology chain supporting a transaction isn't good value, and doesn't solve the bigger problem. Spreading infrastructure investment appropriately across the entire transaction footprint, driven by business requirements and risk, is the way of the enlightened grasshopper.
I would argue that storage alone is not the answer here, nor is HSM (which mainframes had ohhhhh ... a while back), nor is the RDBMS, nor is transactional JMS - it's a little bit of everything, in just the right amounts. Just add beer.
Fetching coat, again.