I have a dell poweredge R730 server with 9 hard drive units already in RAID 5 ... right now I want to add 4 more hard drives and I want RAID 5 again, when I do RAID 5 configuration on 4 hard drive units there is a failure of 2 units the hard drive.
Is there a solution to solve this problem?
One or more of the drives may be faulty or unsupported. Unsupported hardware can have erratic behavior. You can run diagnostics on the drives, make sure all firmware is updated, and try the drives in different slots. Information and downloads should be on the system support page.
Dell EMC, Enterprise Engineer
its very rare, but I have seen drive slots on a backplane fail. you could try deleting the failed raid config, moving the "working" drives to the slots where the drives failed and see if the failure follows the drives or the slots. The first thought that hit me about your scenario was that there was a 2TB limit on early H730 firmwares, but I couldnt find proof of that so far.