Hello! I'm from Russia. I will write with the help of a translator GoogIe. I use Promise Pegasys R6 12 TB. It seems from 2013. I can not remember exactly, I registered the product in the support service in November 2013.
The problem is this. In recent times, the hard drive has become more frequent. And with the disk at first glance, everything is fine. Through the Terminal, I return it to the online. But it still turns red and gives an error that the drive is "Dead." The Rebuild did not produce results. I made a backup, formatted the disks and re-created the Raid array (Logic drive). But after an hour of work, the problem was repeated. This is the top (first drive). I swapped it with the second. And the problem reappeared on the first (!!!) disk. This means that the disk is healthy. What is this problem? Is she related to raid? How to eliminate it? I use High Sierra 10.13.6. The latest version of the utility.
