Are any of the Samsung drives SSD or are all they all m.2?
M.2 drives
are SSD's
I think you mean SATA drives.
There are SATA SSD's, and there are NVMe SSD's. M.2 drives can be either (but most newer ones are NVMe)
Any idea who is the target market for Samsung PRO drives?
I tend to think of Samsung's Pro drives as "pro-sumer" tech. In other words, intended to be found in Workstation, HEDT and high end consumer (who are we kidding, "gaming") machines.
If you ask Samsung they probably won't call them server drives, but as far as client drives go, they have a very good reputation. Or at least used to back before the 980 and 990 Pro's had a well publicized firmware bug that caused serious write amplification issues. (which has since been patched, make sure you update the firmware on your drives using "Samsung Magician", folks)
Heck, I've been buying SSD's since ~2010. The only two brands that I have never had fail on me have been Intel and Samsung drives. (Well, technically my Inland Premium drives havent failed either, but the sample size isn't as large) Every other brand I've bought has had failures.
The worst were the old OCZ SSD's back in the day. Never had one of those last more than 2 years. They would die like clockwork. I've also had a terrible time with Sabrent Rocket 4 drives. 100% failure rate in the 2-3 year time period. (albeit a smaller sample size)
Samsung and Intel - on the other hand - every last one I have ever bought, no matter how hard I have punished them, is still alive and well. And it has probably been ~12 years now.
So, the problem here seems to be Windows Server, not the Samsung drives. I've punished the crap out of a large variety of Samsung Pro drives, 840 Pro (SATA), 850 Pro (SATA), 970 Pro (NVMe), 980 Pro (NMVe), 990 Pro (NVMe) heck, and even some EVO drives for years under Linux (Workstation and Server), and client Windows installs. I've used them as cache devices on ZFS pools, as scratch disks, as VM datastores, you name it.
I have noticed some slight performance degradation as they start filling up (primarily on writes) but I have never even once had a Samsung Pro drive drop out, disappear, reset, crash or lose data. And I have used a pretty decent sample size of the things, much
much greater than your typical forum anecdotal experience.
The common denominator in this thread seems to be related to Windows Server installs. Maybe the NVMe driver is somehow different in the Server edition than in 7/10/11?