VM confusion again

[HCHTech]

So, I'm refurbing a server for the shop, and taking this opportunity to familiarize myself more with virtualization. I've got a couple of new servers for clients coming up next month, so want to break things on my own bench before subjecting my clients to my learning experiences.

I've got two RAID1 arrays in my setup, a 240GB (I thought I'd split this down the middle, 120GB for the host OS, Server 2016 in GUI mode with the Hyper-V role, and 120GB for the OS drive for the single VM, which will be running Server 2016. Then, I've got a 1TB array for the storage drive of the VM.

To this end, I've created 3 virtual disks in the RAID manager (This was my first UEFI server - first I had to FIND the RAID configuration, I spent an embarassingly long time thinking my RAID card was bad before the light dawned), two 120GBs and one 1TB.

So far so good, but I'm getting confused about the actual VM setup. When I install the host OS on the first 120GB virtual disk, I have to have a create a place to store the VHD file(s) for the VM (which would be 120GB is size if it uses up all of the space on it's C: drive), so from within the host OS, I have to initialize and format the 2nd 120GB virtual disk. Then, if I want the VM to have access to the 1TB Storage array, from within the host OS, I have to initialize and format the 1TB virtual disk.

So...my host has a C: drive of 120GB, an E: drive of 120GB, and an F: drive of 1TB.

Then, when creating the VM machine, I would choose to store the VHD file on drive E: (of the host) and assign the VM (up to) 100% of that space for it's drive. Once created, that amount of space shows as the C: drive of the VM. and the VHD file for the VM is stored on the E: drive of the host. I can then go into the settings for the VM and add an additional hard disk, choose to store the VHD for that disk on the host's F: drive, and give it (up to) 100% of that space.

Have I got this right? Obviously, you can't store a VHD on a disk that is smaller than the size the VHD will grow to if it fills up all of the storage allocated to it, yes? I can see that it becomes important to NAME the VHD files so you can identify exactly what you are looking at. VM1OS.vhd, VM1Storage.vhd, VM2OS.vhd, VM2Storage.vgd, etc. Also, the deduplication and other space saving features in Hyper-V may be more important than I thought.

 

[Markverhyden]

Sounds about right. What is the specs on the server?

 

[HCHTech]

Thanks, Mark. I've got a Xeon E5, 48 gigs of RAM, an intel MB & Raid Card, 750W PS & storage as detailed above. I scored a hot-swap drive cage recently, which is what prompted me to put this frankenstein together. Most of the parts came from a home-built-but-with-good-parts unit I picked up at a bankrupcy auction a couple of months ago. Nice big intel case, dual hot-swap PS - sweet.

In Hyper-V, when I shut down the VM and then go into it's settings, there is only one iSCSI controller, so when I specify the 2nd drive, it ends up taking the place of the existing drive, so then the VM won't boot, of course. I can go in and swap back to the existing VHD to set it right again, but I'm missing something when adding the 2nd disk. It's been a long day, so I'll take a look with fresh eyes tomorrow, I'm probably overlooking something stupid.

 

[YeOldeStonecat]

It's broken up a little odd....

For my MS Hyper-V boxes....I usually have a large enough C drive to:
A) Install the Host-OS...
B) Have enough room for a C drive of a few guests. Yes I custom carve out directories for the VHDs of the guests to be s tored in

And then a larger data volume for:
A) Data volumes of the guests
B) Perhaps another C drive or two of lower performance need guests.

This way...the C drives of the guests are split across different "spindles" (volumes). Instead of having ALL of the C and data volumes of the guests on the same RAID volume. You get better performance when "spreading the load".

Make some server virtual drives dynamic (just don't do that on database servers).

Don't forget...the data volume of servers should also be on fast disks. Those are the drives that the end users work from all day every day, they deserve the speed.

 

[Markverhyden]

Which model RAID card? A lot of those Intel's are software RAIDS. iSCSI? I'm confused. iSCSI is supposed to be a mechanism for transmitting SCSI commands via TCP/IP, basically for NAS, etc. Been a while since I looked at Hyper-V but I'd think that they should have typical local type connections, like SCSI, and not be using iSCSI.

 

[HCHTech]

You're right, just a terminology confusion on my part. The card is an RS3DC080, definitely hardware RAID. When I tried it (adding an additonal hard disk to the VM) again this morning, it worked the first time. I think I was just at the wrong level in Hyper-V Manager.

So, since a picture is an easier way to convey meaning, here's what I ended up with:



In Hyper-V manager, in the settings for the VM, just click on SCSI controller, then you can add a hard disk (or DVD or shared disk). I'm not clear on the value of adding a shared disk, I'll have to read up on that. I think last night I was in the top-level settings for the HOST, not the settings for the VM. I note in Hyper-V manager, when you are adding a disk, it doesn't tell you how much space you have to work with, so you have to do the math yourself if you have multiple VMs. Also, I don't know if the size you specify is the formatted or unformatted size, so I fudged a bit and only specified 110GB for the C: drive instead of trying to guess what the full capacity was. Also, I chose to same some capacity on the 2nd array for future use. These are SSDs, which is why the capacity is smaller than it would have been if I had used spinning disks.

Also, I'm trying to emulate what I'll be doing for a customer next month, just a single VM on the box. They have an existing domain controller, and need a standalone server to run a practice management software. I'd like to spec that one so that when it comes time to replace their existing domain controller in a couple of years, we can just add some RAM and drives to the host and just create an additional VM for the new domain controller.