So, let’s try to entertain this one.
In the original log output, the file that the program is having problem with is ~800 GB in size. That file has “plot.2.tmp” extension, so we can assume that potentially “plot.1.tmp”, etc. are already sitting on the disk. If we assume that two / three such files are being created, we are somewhere around 2 TB mark at that moment. Maybe the problem is with the RAID array that is for some reason limiting access to 2 TB only? Again, my take is that OS is most likely stable, so this is just a long shot again. However, your RAID settings / drives are what is common between those two boxes.
I would try two things.
First, I would try to create a big file (say past 2 TB). You can use copy command to concatenate files, so that would be something like:
copy a + a + a b // used file a (preferably a big one; some zip file if you have one on hand, maybe some ISO file) to create file b; also, I would repeat that "+ a" few more times to get faster with the big one
copy b + b + b c // and so on, every time using the previously created file to get a bigger one
Once you get to 500 GB, just do 5x that 500 GB, and see whether it will go smoothly. This will let us know, whether your RAID will let the user to cross that ~2 TB mark.
The second test would be a check, whether you can trigger the same error, but by you forcing the limited free space. Just create a 1.5 TB file (or combined) before you start plotting (so it has that 2.3 that is advertised as needed). Once the plotter will be busy, using the first method, create another 1 TB or so of files, so you will push your files to about 2.5 TB or so, basically forcing the plotter to barf. I would be really interested to see whether the error message will be the same, as what you have in that first log.