I was hoping to have figured it out by myself, being a Linux intermediate, so I took it to a professional in the city, and while I was there, I was showing the tech guy step by step what is happening, and he immediately seemed to know what it was, it seems it was a phantom LV bound to the LVG, which didn't show up using the standard lvdisplay command, he had to manually remove the device from /dev then use dmsetup to remove the bound LV from the LVG, rebooted and voila, success.  Only 1 LV should be present, and that's the boot volume, the rest of the drive is ext4, with exception to the swap partition. What he explained was, somewhere down the line a new logical volume (LV) was created (not by me, I don't think), and when whoever, tried to delete it, didn't follow the precise procedures to remove it completely from the logical volume group (LVG), so, when the server was being rebooted, maybe after a physical cleanup, or an upgrade, or whatever the reason, the OS was still trying to read the extra LV's that didn't exist, and thus thinking the allocations sdc and sdd were physical drives and tried to read from them to verify existence, and failed, thus displaying the error.  Now it's been fixed, the server boots fine now. NoteI refer to 'drive' instead of 'drives' as when using RAID 5, writing to them is seen as only writing to one drive, even though I have 6 drives attached.
Hi, y'all, sorry about the username, but every name I try says 'Username in use", so by just using a bunch of random letters, there'll be absolutely no possibility of that username being used lol Anyway, to the question in hand. I have a PowerEdge T710 with 6 1TB Hd's setup as RAID 5, and last year I installed the iDRAC 6 Enterprise module so that I can have remote control over the KVM virtual console, anyway, it's been working perfectly up until yesterday, when I try to boot, into Ubuntu Server 20.04 LTS, the boot sequence is fine, but it doesn't even get to boot properly, and hangs on 'SDC unable to continue OS, medium not found", SDC is a partition on the RAID disks and Linux allocated the letters sdc as the main partition, sdc1,2,3 as sub-partitions, 1,2 and 3 respectfully.. Now when I booted in the PERC bios PD manager, shows all HD's as being online, no errors, S.M.A.R.T status = No Errors, so what can it be?  Sda, is the primary drive allocation, sdb is a mounted partition, as is sdc, but Ubuntu sees sda, and sdb but not sdc, Ubuntu won't continue booting unless sdc can be read from.   Any solutions?
PERC shows HD's online, but Linux says 'Medium Not Found'