SoftRAID RAID-0 on OWC ThunderBay 4 mini fails

Subject: SoftRAID RAID-0 on OWC ThunderBay 4 mini fails

This problem caused a lot of time/effort to uncover. So bear with me as I describe the scenario.

The Hardware
OWC ThunderBay 4 mini (Thunderbolt 2) with 4 OWC Mercury EXTREME Pro 6G 120GB SSDs.
It's the first unit in a Thunderbolt daisy chain with a 2nd unit being a Belkin Express Thunderbolt 1 dock.

The Software
Running Mac OS X 10.11.5 (Build 15F34) - El Capitan
SoftRAID used to configure the 4 SSDs as a RAID-0

The computer being used
Late 2015 27" iMac 5K Retina (4GHz Intel i7, 512 SSD, 32 GB RAM).
The ThunderBay 4 mini is attached to the first iMac's TB-2 port.
There is a Pegasus2 R6 (Thunderbolt-2) and a Pegasus R4 (Thunderbolt-1) attached to the iMac's 2nd Thunderbolt-2 port.

The problem
50% of the time when cloning around 100GB of data to the ThunderBay 4 mini using Carbon Copy Cloner (CCC) the operation stalls, the ThunderBay 4 mini 'disappear' or goes offline and the system within a very short time displays a spinning beach ball for anything I try to do.
When this issue arises the devices attached to the Belkin dock are fully operational (my test had an i/o test running to a USB3 disk attached to the Belkin Dock, and it continued after the CCC operation stalled). This indicates the Thunderbolt 'pass through' in the ThunderBay has not failed.
The power LED stays on for the ThunderBay.

The problem has never occurred when I configure JUST 3 of the SSDs in the ThunderBay 4 mini as SoftRAID RAID-0. I've also varied the individual SSDs used for the 3 SSD RAID-0 configuration to eliminate a faulty SSD.

Using SuperDuper! (SD!)as done using CCC above, also results in the same issue. This tells me the issue is not being cause by CCC or SD!.

My thoughts so far are...

1) I don't believe the ThunderBay 4 mini is faulty
2) The problem may be associated with the SoftRAID software (driver included)
3) The problem may be associated with Mac OS X Thunderbolt driver software
4) The system.log so far has not offered me any clues
5) I've discussed this issue with OWC and have sent them SoftRAID log files and they've not found any issues so far. They are still investigating.
6) Given that 4 SSDs as RAID-0 fails 50% of the time and that 3 SSDs as RAID-0 do not fail at all I'm leaning toward some kind of time-out occurring that the Mac OS X does not take kindly to or some issue with SoftRAID itself. The 4 SSDs can provide almost 1400 MBytes/sec whereas the 3 SSDs provide around 1000 MBytes/sec
7) When the problem arises no more messages are being logged in system.log.
8) So, my thought at this time is that the issue is with the Mac OS X or SoftRAID not handling this ThunderBay hardware correctly.

One of the last messages in the system.log as this problem catches my attention and is as fvollows...

May 21 12:58:54 Barry-27-inch-iMac-5K-Retina com.apple.kextcache[5814]: /Volumes/ThunderBaySSD 4x RAID-0 locked; waiting for lock.

It seems some kind of lock is being left set and the OS or SoftRAID's disk queue disk queue gets stuck.

To rule between Apple's Mac OS X and SoftRAID causing this problem I decided to configure the ThunderBay 4 mini's RAID-0 using Apple's Disk Utility. this was done and further test was done as follows.

1) I created an Apple RAID on the 4 SSDs in the ThunderBay using Disk Utility.
2) I ran five SuperDuper! 96GB clones to it without any issues/stalls.
3) I ran five Carbon Copy Cloner (CCC) 96GB clones to it without any issues/stalls.
4) My conclusion is therefore that SoftRAID is the cause of the stalling problem.
5) I will be submitting a problem report to SoftRAID (this is the report).
6) I will indicate my findings to OWC.
7) I will submit a PR to Apple on this issue as a 3rd Party issue.

Please have this issue submitted to the Technical team for their assessment. Thank you.