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I am brand new to the world of servers and system admin., but I recently stumbled upon a used server in good condition:

Dell Poweredge R720, 2x E5-2640 12 Cores (2.5 Ghz), 128GB RAM, 8.2TB of drives (two of which are SSDs)

I've set up multiple VDs and installed various OSs on them. They vary between RAID 0, 1, 10, and 5. I can also boot into each and they individually work great.

However, it just now hit me that I have no idea as to whether these things are meant to ever boot/run more than one VD/OS at any given time (I'm used to typical home PCs, which I've always understood to be able to boot only one OS at a time).

Based on a few hours of googling, I can see that there are many examples out there of people setting up multiple VDs on a single RAID controller, and people sometimes even seem to imply that they've set up one VD to run as the app server, and another to run a corresponding DB server (which seems to me like a reason to believe these things can be run simultaneously). But maybe the latter is simply a VD for holding raw data, as opposed to a second bootable VD/OS that runs DB software thereon?

So my question is: is it possible to boot/run more than one VD/OS at a time, given my particular hardware setup? I'm thinking the answer is supposed to be so obvious, no one bothers writing about it on the Internet.

P.S. this is my first time posting here, so please kindly let me know if I need to make edits to make this question more conformant to how things are done around here :) thank you

dan
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It seems that you asked 2 different questions, one in your title and one in your question body, so I'll answer both (in the future, try to keep your title and body consistent).

Regarding your question about running multiple RAID arrays simultaneously, this is definitely possible. All you need to do is just plug in multiple RAID cards to manage multiple arrays. You could also use software RAID, but this does put more stress on your CPU so It's best to be careful with it.

With your other question about running multiple OS's simultaneously, this is possible using a hypervisor. This doesn't run the OS on the bare machine as the hypervisor provides a layer between the hardware and the OS, though this also doesn't decrease performance much for most workloads. If your machine has Windows Server installed, you can use Hyper-V to manage virtualization, and if it has Linux, you can use KVM. Alternatively, you could install a type-1 hypervisor directly to the server such as ESXI. Your hardware can easily run a hypervisor, but your performance is limited by what you run on each virtualized machine.

Bryan Perkins
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  • Thank you for your advice and answers. I see now that the two questions I asked are indeed distinct (but I assume editing it at this point is not recommended..?). I've decided to install and use KVM over Ubuntu server for my needs. Since I can't seem to create a VD/RAID array that spans both SSDs and HDDs (but I want to make use of all my drives) I now have other questions, but I will do more research before posting again. Thanks again! – dan Oct 15 '18 at 17:28
  • Hyper-V is a Type-1 hypervisor. There is also a 100% free "headless" version of it that can be managed through commands (cmd and powershell) or through Windows Admin Center (also free). Also, according to this, you can have multiple RAID arrays on one RAID card: https://superuser.com/questions/384590/can-i-run-multiple-raid-arrays-on-a-single-raid-card . But I am not an expert on RAID, so take this with a grain of salt. There might be performance bottlenecks from this. – NoOne Mar 04 '20 at 17:14