5820: can I make it boot a Windows NVME drive from another machine?

Hello,

the 2nd mini SAS already goes to the drive bay next to the one having the nvme now.

You have 4 bays and they can be configured in 2 different ways

Way 1 :

sata sata

sata sata

Way 2:

nvme/U.2  nvme/u.2

sata sata

In the free bay next to the nvme you can install uniquely either a nvme drive ( with an adapter ) or an enterprise u.2 ssd

@mazzinia_​ Thanks. If I plug a 2.5" or 3.5" SAS drive into  the drive bay next to the one having the nvme will it work? It is interesting, because I got a strange light when I tried to plug a SATA HD in there.

The nvme drive which came with the system goes into an aluminium/plastic sleeve and slots into that bay. Is that a U.2 ssd adapter? 

@IceStation​ it will not work, as I mentioned it's converted to have either a nvme m.2 (using a dell adapter like the one in the other bay, that has to be sourced separately / or using a 3rd party suitable adapter) or a 2.5" U.2 enterprise ssd.

You cannot plug sata or sas (mechanical) drives (simply because that's not SAS)

@mazzinia_​ Thanks again. I saw a video where someone took the 5820 apart and showed exactly my set up. One 1tb nvme with the adapter in one top slot, and the possibility to put a U2 drive into the second slot. Then the bottom two slots are both for SATA.

So you need a SAS card and appropriate cabling if you want to install SAS drives. 

It is strange that mini-SAS is mentioned. But it will probably be clear when I read more.

Any thoughts on why the drive from HP won't work?

Your HP Z840 was likely built with Haswell processor and hardware components from 2014.  Therefore, the boot drive was containing some Legacy settings in boot mode.

Your Dell Precision 5820 was built many years later, probably with Xeon W processor, Cascade Lake or similar.  UEFI firmware and other BIOS advanced security boot mode may have detected conflict settings from the HP boot drive and would not boot due to incompatibility.

Second question, my Dell 5820 says it has two mini SAS ports, one of which goes to the nvme drive bay. Can I connect the second mini SAS port to a SAS hard drive?

No, you can not connect miniSAS port to as SAS hard drive because both of the ports are already being connected to the upper flexbay and despite the name, the backplane that connected to miniSAS port does not support SAS drives.

In addition to the valuable information from mazzinia about your flexbay hardware, just want to let you know that the drive bay next to the one having the NVMe can be utilized with another NVMe using a U.2 adapter such as this one.  Put an NVMe SSD in the adapter, install the adapter into the drive bracket with 2.5: adapter and it will be ready.

Thanks for the tip about buying a cheap U.2 adapter to fit into the second slot. I've seen these for sale in various venues. I ended up buying an 800 GB enterprise SAS SSD to try in that slot. It if doesn't work I'll use it somewhere else. 

I cloned the Crucial P3 4tb NVME I was using, in the u.2 adapter, onto a 4TB SATA hard drive which I placed in one of the lower, SATA, drive bays. It boots Windows 11 fine. There is nothing wrong with the OS image on my NVME drive. Another NVME works in that u.2 adapter. It seems that the drive isn't compatible with the 5820 or I need some kind of firmware.

@IceStation​ the 800GB enterprise ssd will work, I've a 1.7GB u.2 in my 7820 and didn't make a fuss aside not properly light up the lights on the caddy ( the HB light is on, the operation light isn't. while the m.2 in the dell adapter has the HB on, and operation light working ).

Only way to not work is if it's a brand/model requiring drivers that are behind a paywall and thus hard to get.

@mazzinia_​ Thanks again. It is great news that my 800gb SAS enterprise SSD will work in the U.2 in my 5820. I checked it in my HP Z840 (which has SAS), and this device has only been powered on 10 hours. So it was a great buy for under £30. 

It wasn't recognised in the Dell, but now I know it should work I'll try again. I have a couple of projects, and I could use it in a NAS if it doesn't play out. 

@IceStation​ it wasn't recognized in the Dell ? could you write the brand and part number, if not an issue ?