Hi all.  I am basically asking what the titles says.  I am currently configuring a HTPC with windows 10 and Kodi using a SSD.  I will be running emulators on it as well.  Now that I am about done I am reading about virtual machines with Unraid and wondering if I should have went that route?  I've read plenty of positives about virtual machines.  Are there any negatives or should I get started on building a VM too . 

Some negatives for virtual machines as they apply to unRAID:

 

They can be tricky to backup, although I believe some solutions do now exist.

 

They could be tricky to port to another unRAID server.

 

No replication mechanism exists that I know of allowing you to replicate an existing vm from one unRAID server to another and by this I don't mean a copy job, but something more elegant like what Veeam offers with Esxi and Hyper-v.

That doesn't seem like too much of a downside as long as there isn't any vital data on it.  It's something to think about.  Thank you!  Is the speed something comparable to having it installed locally?

The speed of a VM won't be as fast as a native install; but with modern CPU's with hardware virtualization support it's still very acceptable ... the virtualization overhead simply isn't a significant factor.

 

Amazing.  I will give this some serious thought.

Actually if you install your VM on an SSD, you can achieve very near bare metal results. I have a W10 vm installed on unRAID 6.18 and I am passing through an Nvidia GTX 960 and I can play Star Wars Battlefront which was released in 2015 perfectly, no hiccups, slow downs, nothing, smooth as butter. I have the vm configured with two CPU cores of my 8 core processor and 4GB of RAM, it works just fine and running the VM on its own dedicated SSD I think makes all the difference.

Actually if you install your VM on an SSD, you can achieve very near bare metal results. I have a W10 vm installed on unRAID 6.18 and I am passing through an Nvidia GTX 960 and I can play Star Wars Battlefront which was released in 2015 perfectly, no hiccups, slow downs, nothing, smooth as butter. I have the vm configured with two CPU cores of my 8 core processor and 4GB of RAM, it works just fine and running the VM on its own dedicated SSD I think makes all the difference.

 

You bring up a good point.  I do have a SSD cache drive currently.  I currently have a 3 core AMD processor and 8GB Ram.  I recently upgraded the ram because my dockers were using up to 80% of my former 4GB ram.  Should I probably look into a hardware upgrade if I went to a VM?

I think it all depends on what you want to do overall, what is the big picture for your unRAID server. I built the windows vm because I had the server laying around ( I have three unRAID servers) and I wanted to test the GPU passthrough and see how well it would work. From the sounds of it, your current hardware seems a little limited but that all depends on what you want to do. My unRAID server that I built the windows 10 vm on has a quad core i7 processor, 16GB of RAM and an SSD dedicated to the vm, coupled with the GTX 960 that gives me a pretty powerful gaming VM. If you want to achieve something similar, then sure, you'll need to upgrade.

Actually if you install your VM on an SSD, you can achieve very near bare metal results. I have a W10 vm installed on unRAID 6.18 and I am passing through an Nvidia GTX 960 and I can play Star Wars Battlefront which was released in 2015 perfectly, no hiccups, slow downs, nothing, smooth as butter. I have the vm configured with two CPU cores of my 8 core processor and 4GB of RAM, it works just fine and running the VM on its own dedicated SSD I think makes all the difference.

 

I agree.  I may put a VM off for awhile until I can do a hardware upgrade. I think it would overly stress my hardware running all of my current dockers plus a VM.  Thanks for all the input!

I definitely agree r.e. using an SSD for the VM's.    I have a 1TB SSD dedicated to my virtual machines; and they perform very nicely.

 

As I noted, it's not as good as bare metal (the same OS on a bare metal SSD will easily outperform a VM), but it's not enough to make a major difference with modern CPU's.  Any 4th gen or later Core i5, i7, or E3 series Xeon will run VM's very nicely => and even lower end CPU's do fine as long as you're only running a single VM.

 

slight thread hijack... is there a good how-to for VM's on unRaid? I tried searching and didn't come up with anything. I likely missed it.

I definitely agree r.e. using an SSD for the VM's.    I have a 1TB SSD dedicated to my virtual machines; and they perform very nicely.

 

As I noted, it's not as good as bare metal (the same OS on a bare metal SSD will easily outperform a VM), but it's not enough to make a major difference with modern CPU's.  Any 4th gen or later Core i5, i7, or E3 series Xeon will run VM's very nicely => and even lower end CPU's do fine as long as you're only running a single VM.

 

Gary have you tried rather than creating a vdisk for the vm actually passing through the whole disk for the vm. I have done this with mechanical drives and result is very good. I am sure passing through a whole ssd would give excellent performance

Haven't tried that, but I'm sure it would work very well.    Don't misread my comment r.e. "... it's not as good as bare metal ..." ==> that does NOT mean the performance isn't VERY good.  It's simply always true that a bare metal implementation will be slightly better than a virtualized machine, since there is ZERO virtualization overhead.  But on high-end hardware the difference isn't likely to be enough that a typical user would even notice it -- it's like benchmarks where you can SHOW that there's a difference in performance between two things; you'd not likely ever notice it.   

 

That said, I'm a HUGE fan of virtualization -- I have over 50 VM's (most are very rarely used).    And with VM you can have multiple machines running simultaneously => a FAR more convenient state than, for example, a multi-boot system that runs everything bare metal -- but only one OS at a time.    In addition, with virtualization you can run obsolete systems that wouldn't work on your modern hardware => e.g. DOS, Win 95, Win98, XP, etc.

 

I have a few vm's on a few machines. They operate at about a 3-5% loss in cpu performance vs bare metal. No big deal. Also nice to be able to remote into my network and access any of them.

Adding my support for running VM's on a SSD. I had ran mine on a spinner at first and the speeds were abysmal, taking considerably longer to boot.

One other slight negative is that the array has to be started for the VMs to be able to start.  Limetech has mentioned they may introduce a feature to allow VMs to start with the array stopped, but there's no ETA that I'm aware of.

 

For example let's say you use a pfSense VM in unRAID to be your primary firewall/router, in order to have pfSense running you need to have the array started.  When you have a failed disk or need to stop the array, you lose your router/firewall, internet access.  You can bypass pfSense by re-cabling directly to your DSL/cable modem and possibly remapping static IPs but it's a bit of a hassle.

 

I ran pfSense as a VM in unRAID for a year or more but just recently built a new low power server to run pfSense because each time I needed to stop the array the internet would be OOS, would be a pain to rewire, redo static IPs, family would complain, etc.

 

I do run a few Windows 7 VMs to transcode audio, video, run syslog and other misc servers.  VMs are very useful!

Never thought of that.  That's a good point that the array would have to be online in order to work!  Seems like VMs would be very useful.  MIght be about time for a hardware upgrade!

Downsides of virtual machines....um i cant think of many....

 

Well ok you cant create a load of virtual machines turn them into real machines and sell them on ebay .....because are virtual lol

It would be cool to be able to. Well you can take a real machine and make it virtual. just wish I could do it the other way!

I would never have to goto work again every time i needed money i would just create a vm !!!!

 

Ok im sorry a stupid answer but hey  :)

 

 

Gary have you tried rather than creating a vdisk for the vm actually passing through the whole disk for the vm.

 

This intrigues me.

 

My WIN10 VM lives on an SSD cache pool.  However, I have a 2TB USB3 hard drive (2.5") connected to a controller that is stubbed.  The WIN10 VM has exclusive access to that controller (and drive).  I use this drive as the game library for that VM.

 

While this works *well*, would a better option be to create a 500GB vdisk (G: drive) and use that for the game library?  Also, what are the thoughts about putting said vdisk on the array?  Is that even a viable consideration?

 

john

Gary have you tried rather than creating a vdisk for the vm actually passing through the whole disk for the vm.

 

This intrigues me.

 

My WIN10 VM lives on an SSD cache pool.  However, I have a 2TB USB3 hard drive (2.5") connected to a controller that is stubbed.  The WIN10 VM has exclusive access to that controller (and drive).  I use this drive as the game library for that VM.

 

While this works *well*, would a better option be to create a 500GB vdisk (G: drive) and use that for the game library?  Also, what are the thoughts about putting said vdisk on the array?  Is that even a viable consideration?

 

john

 

I think running a usb disk for a vm would be a bit slow (but then i havent tried it so dont really know!)

But if you are running a usb disk you dont need to passthrough a usb controller to use on your vm. When you attach the usb to unraid it should come up as an unassigned drive (so long as not connected to a stubbed controller).

Find its id number and pass the disk through.

My code for that is here

<disk type='block' device='disk'>
      <driver name='qemu' type='raw' cache='writeback'/>
      <source dev='/dev/disk/by-id/ata-ST31000528AS_6VP41EPS'/>
      <target dev='hdd' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
    </disk>

Obviously if you could attatch a physical drive to a sata port rather than usb would be better.(faster)

A vdisk would be ok, but never put it on the array. With the the parity it will be so slow.

 

A vdisk would be ok, but never put it on the array. With the the parity it will be so slow.

 

Are DISK shares considered part of the array?

 

A vdisk would be ok, but never put it on the array. With the the parity it will be so slow.

 

Are DISK shares considered part of the array?

yes.

If I want to create a vdisk just for games folder, like Steam, GOG, Origin etc then create the vdisk on a HDD that is not part of the array, ie an unassigned disk, or just buy a higher capacity SSD and add to my existing Cache pool?