Hi guys. So, this probably isn't an Unraid problem at all, but I thought there'd be no harm in asking the experts.
Anyway the situation is, I have a server (intel S2600GL based) with which I'm using an old Adaptec 5805 PCIe raid controller (Intel's own RAID configuration utility terrifies me, which is why I didn't use the controller that came with board). A while ago I bought some new Seagate Exos 6TB SAS drives. These are SAS 12Gb/s drives, which are to my understanding backwards compatible with SAS 6Gb/s controllers and interfaces. For now I have them configured in RAID 1 - probably not the ideal way to use Unraid, but this system has evolved over a period of years into something of a Frankenstein, and it's quite complicated, so this is where it's at as of now.
The problem I have is that after every power down I have to physically go to the server, enter the RAID configuration utility and rescan the drives in order to get them detected. At power on I can hear the drives spin up, activity lights flash and whatnot, but the controller just doesn't seem to catch them before it's finished its POST. After rescan I can exit the utility, reboot and it'll run perfectly fine for months, then at some indeterminate time something happens and the drives disappear from Unraid. My best guess is the controller pulls the drives to protect the data. (a hardware RAID thing I think?)
It takes a power cycle, rescan, reboot to get the drives detected with logical volume status 'optimal' and make Unraid happy again. So far I've tried moving the drives to different slots on the backplane, but the problem eventually reemerges. Since this problem only began when I installed the new drives, I'm inclined to think there is some incompatibility between drives and controller, but I wouldn't even know where to start with diagnosing that.
Could it be I simply need a newer raid controller? My backplane only has the old type sff-8087 connectors, although I think I've seen adaptor cables online. For now I have all important data backed up and the only thing keeping me from messing with it more is the prospect of downtime and it doesn't seem to have reached the threshold of brokenness where it becomes worth fixing. I'd just like to hear ideas or if anyone has experienced anything similar.
(apologies for incoherent rambling)