SoftRAID 6.3 Certify SSD Problem

UPDATE: I have an OWC Thunderbolt 3 8 drive enclosure (awaiting RAID6!) and an Apple Thunderbolt 2 to 3 adapter.  I installed both of the SSDs with certify (write) failures and now they are both being certified.  There has to be a real issue here.  I'm convinced this is not a red herring.  Why do both drives in a Thunderbolt 2 enclosure fail certify writes immediately?  Remember the same drive also failed a normal write when configured in a RAID5 volume.

@mbt_utp 

Note first: "Certify" is a low level macOS script (kind of like using dd in terminal) that does not use the SoftRAID driver at all. Its a stable piece of code that has not changed much in 20 years.

So the issue must be hardware.

What is your enclosure? Does it specifically support 4TB drives? They take more power, I know several enclosures that cannot take 8TB NVMe blades, for example.

It is NOT due to insufficient power (P=I*E).  Both SSDs were installed with NO other drives in the enclosure (OWC ThunderBay 4 with Thunderbolt 2) and failed certify, apparently on the first write sequence.

"must be hardware".  I'm coming to a similar conclusion since BOTH drives appear to be certifying when installed in an OWC ThunderBay 8 with Thunderbolt 3 (still not a "power" issue).  I successfully certified 3, simultaneously, of the 5 Samsung 870 EVO 4 Tb drives in the same OWC ThunderBay 4 with Thunderbolt 2 where the other 2 drives failed.  This OWC ThunderBay 4 with Thunderbolt 2 has operated without incident with 1 TB SSD drives for well over a year.

Why would certify fail the initial write sequence to a drive? Timing? What are the fundamental differences of the protocol layers of the interfaces involved (USB 3 to SATA, Thunderbolt 2 to Enclosure to SATA, Thunderbolt 2 to Thunderbolt 3 adapter to enclosure to SATA?

There is a real issue using Samsung 870EVO 4TB drives in the OWC ThunderBay 4 with Thunderbolt 2 enclosure with the Mac Pro 2013.  I'd think OWC and SoftRAID would want to know about that.

Consider the issue closed, I'll reconfigure my storage architecture and forget about understanding the 'Why' behind the issue.  It simply isn't worth the frustration and time consumed/wasted.

Maybe this OWC knowledge base article requires an update < https://eshop.macsales.com/Service/Knowledgebase/Article/10/737/ThunderBay-4-Incompatible-25-inch-SSDs >

@mbt_utp 

I will get this updated. What I do know is first generation of most Samsung drives are not mac compatible. They add that later, after they start shipping to the market.

As you are aware, writes should never fail, as writes are done blind. When writes fail on the first I/O, it is a communication issue most likely. What you are doing is the equivalent of using this command:
dd if=(data or device) of=/dev/rdisk4

If you were duplicating a disk, a simple version of dd is:
dd if=/dev/rdisk1 of=/dev/rdisk2

(input file from some either another disk, or in our case a file/set of data. the target is the output disk number.)

This is in simplistic form, what the certify does Then it reads back the data and makes sure the checksum is OK. last pass is all zero's.

So if certify fails immediately, the device cannot be written to. Why is the question.

the bus protocol should not matter, its in a layer that is below this one.

Despite a successful certify of the Samsung 870 EVO SSDs back in late August, after a few months of use (1400 hrs) SoftRAID reporting I/O errors on one of the drives in a RAID5 configuration.  The drive reporting errors was replaced with a new drive, but the RAID could not be rebuilt due to Read errors on one of the remaining drives.  Given support never offered a solution or even a viable idea to solve $2000 worth of SSDs that fail to operate in an OWC enclosure, I scoured the internet in the hope of finding an idea.  Over in Linux land, some reported success with 870 EVOs after applying Samsung's firmware update SVT02B6Q.   It was a painful process, but now all 22 of my Samsung 870 EVO SSDs are on the current firmware and the 4TB units certified without issue and the backup restored.  Only time will tell if this is the solution.  It is unfortunate that the number 1 producer of SSDs in the world, never had their products tested in OWC enclosures by OWC.

@mbt_utp 

I have seen for 5 years now, Samsung releases flash media with compatibility for PC's only. then, after weeks/months, they release the "Mac compatible" versions. there is never announcements on this and the last I checked, Samsung firmware updater was Windows only.

So the moral of the story, is only buy Samsung products for mac OS if they are at least 6 months shipping and are "fresh" inventory. It is a sad state of affairs.