I am having issues (new in the last week or two) copying from one Pegasus2 R4 8TB (Raid 5) to another of the same make/model (via separate Thunderbolt ports on back of MacPro), and to/from external drives (Firewire, USB or Thunderbolt connections). The RAID 5 setup is stock from the factory. I able to access and edit existing projects, I just cannot copy anything new to the drives or backup anything off the drives.
Copying a large package file 300GB or larger is stopping randomly part way through, sometimes giving an error -50, sometimes just freezing the finder copy pop-up window with no error or other indication. I have to do a power button shut down of the computer to get control back of files on the drive. Smaller files in the 4GB range have copied OK so far.
I have run Disk Utility, Disk Warrior, and the Promise Utility for both drives shows all green checks for system status.
I also tried running Disksomnia too with no change.
I can copy from one external drive to another with no issue.