Even if Cisco specified to disable write cache, this is AWFUL, SLOPPY engineering.
Apparently Cisco is still as storage-stupid as they were when they bought Whiptail, then re-named it Invicta and then had to flush it all down the drain when they realized it was hopelessly broken.
The on-disk DRAM write caches that exists on every HDD and SSD on the market have been there forever. There are literally dozens of ways that a BIOS, an OS or an application can (and indeed are meant to) control whether writes are being cached on disk or not. That Cisco's engineers would fail to ensure system-level checks to ensure that the write-cache is off when it is supposed to be off is ludicrous.
Hey Cisco product managers, I know a few dozen storage engineers who know this stuff cold and would never have let you goof this up. Maybe stop putting networking engineers in your server/storage business and hire some real talent?
I sure hope the team that did due diligence on Springpath knows more about storage than the ones who presided over the Whiptail and Atlantis fiascos...