> why can't one transaction be completed in less than 1 million CPU instructions
Transactions in this system are almost certainly network bound. The relevant CPU overhead is likely trivial—-likely comparison and not arithmetic in nature even. In that context “add more NICs” is effectively an exercise in horizontal scaling. On top of that any network operation has consistency concerns to contend with.
You could contrive a system that is block device I/O bound but it’s likely to have significant network overhead as most block devices are network attached these days anyway!
Transactions in this system are almost certainly network bound. The relevant CPU overhead is likely trivial—-likely comparison and not arithmetic in nature even. In that context “add more NICs” is effectively an exercise in horizontal scaling. On top of that any network operation has consistency concerns to contend with.
You could contrive a system that is block device I/O bound but it’s likely to have significant network overhead as most block devices are network attached these days anyway!