How To: Getting SMART data from Hyper-V

[Jeff]

Sorry if the title may be misleading.

Unfortunately, the Hyper-V disk passthrough driver does not pass along SMART data from the "host" drive to the VM. That means that there is no way to get Scanner to display this data in the Virtual Machines.

 

However, you can run two copies:

One on the Host, and one in the Virtual Machine. (yes, not ideal, but you do get a discount on the price)

 

On the Host version, disable the disk scans.

To do this, right click on one of the disks that are going to be (or already are) passed through. Then click on the "Disk Settings" option.

On this window, check the "never scan surface automatically" and "never scan file system automatically".

  

 

 

 

 

 

Once that's done, you don't need to do anything on the Guest VMs, as they just won't get SMART data.

I'd recommend setting up email notifications so that you know when you're getting SMART errors.

 

 

 

Original Post

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Hi there,

 

I just downloaded Scanner for my virtualized WHS 2011 setup, which runs within Hyper-V Server 2012.  Each of my data drives are passed through to WHS.  However, Scanner says it can't read SMART data from any of the drives.

 

My understanding was that Hyper-V did pass through SMART data to the guest OS.  Is there some trick to enabling this?

 

Thanks!

Edited September 7, 2013 by drashna
Instructions for Hyper-V

[Christopher (Drashna)]

Unfortunately, no HyperV does not appear to pass along this information, even if you pass the disk through.

 

However, it *will* still read the SMART data in the Host OS. While Scanner and DrivePool are not tested on Server Core installations, they do appear to work (on 2012 Core only though).

However, if you want to get SMART info, as well as scanning of the disks.... you'd need it for both "machines".

[Jeff]

Shoot, that's a bummer.  Two of my drives seem to run a little hot, even though there's a fan blowing across them.  The reason Scanner looked good is so it could monitor the temperatures while files were being moved around.

If Scanner can't access temperature or SMART data from any of the pooled drives when it is virtualized, is there any benefit to having it in that environment?  (And running it on the Host OS seems like it would nullify a lot of the features.  The drive is "offline" to the host OS, seems like Scanner couldn't do much.)

[Mick Mickle]

Jeff,

 

I've been using Scanner on both a WS2008R2 host and Hyper-V guest WHS2011 since last Fall with good performance. (You can probably still get a bargain discount for an additional Scanner license.)  However, Scanner would have to work on your host, and Drashna indicated it might not on Hyper-V Server 2012.  You should be able to test it yourself in trial mode on the Hyper-V core.

 

On the host, Scanner reads temperature and SMART data from all the drives, even the ones that are offline and being passed through to the VM. 

 

Here's what Alex told me in a support contact on coordinating Scanner use in both the host and a guest last October, which I've been doing:

 

"If you don't have SMART data (such as when using Hyper-V), the Scanner can only warn you at the first sign of data loss, in order to prevent further data loss. If you have SMART data, then Scanner will monitor the various counts of sector reassignment and will let you know of any potential developing issues. But this is not possible when using Hyper-V as I will explain later.

 

"Hyper-V virtualizes the disk controller. In other words, all commands that get sent to the drive have to go through this virtual controller. When I last tested it, the virtual controller refused to forward any kind of SMART commands to the drive. Because of this there is really nothing that Scanner can do to get SMART through these virtual controllers. Microsoft has to implement SMART support, there is really no other way.
 

"If you want to run Scanner on both the Host and Guest, in order to take advantage of file evacuation, I would suggest you do it like this:

Turn off Start / stop automatically on the Host. This will prevent surface scans from starting, while still monitoring SMART.

Install Scanner 2.2 and DrivePool 1.2 on the guests with the default settings. The default settings will perform surface scans and will evacuate files when damage is detected.

The only thing that you won't be able to get working is file evacuation on SMART warnings. But this is not enabled by default, so I don't think this is a big loss."

[Jeff]

Thanks Mick!  That was a big help.  I think I understand.  Scanner on the host will monitor SMART but won't do surface scans.  Scanner on the guest will do surface scans (which I think means it will read through every file periodically over time to make sure nothing is corrupt).  If a corrupt file is found, it will create a new duplicate copy on a different drive from the other remaining duplicate.

 

Sounds like the only thing that won't work well is halting StableBit operations if the drive gets too hot.  And that's not that big of a deal.

[Christopher (Drashna)]

Jeff, that's pretty much exactly right, on both.

And yeah, Mick is right about that.

 

On the plus side, if you have purchase DrivePool, you would get the discount on both copies of Scanner, at least.

[Mick Mickle]

Jeff,

 

Also, Scanner on the host will do more than you would expect on the offline, pass-through disks: It will perform a surface scan on all of them (but can't check the file systems on offline disks). That's why it's recommended to turn off "Start / stop automatically" since the guest will be already doing that job.  However, if you check "Never scan surface automatically" and "Never scan file system automatically" in the settings for the individual offline disks (the second option is probably unnecessary because it wouldn't find the file system of an offline disk anyway), then you can turn on "Start / stop automatically" and that will apply only to the disks that are online for the host.

[Jeff]

Awesome, thank you both.  Not too happy about buying two copies of the same software for the same computer, but it beats losing data.

[servonix]

I know this is an extreme necro post, but I figured it would be the best place for a suggestion as it is directly relevant to the topic. Has there been any thought given to implementing a way to link two instances of scanner running on both the host and a guest vm to pass through S.M.A.R.T. data to the guest when passthrough disks are used? Ideally this would also tie in with drivepool's scanner balancer as well to automatically evacuate a drive that is showing issues. As long as both copies of scanner are aware of drive models, serial numbers, etc. then there should be enough data to correlate drive identiy between the host and guest. Obviously communication between the two would need to happen over the network, but I would think the existing remote control features could be leveraged for this. Just figured I would ask whether this is something that could be done as it would make hyper-v passthrough disks more viable with less drawbacks.

[Shane]

23 hours ago, servonix said:

Obviously communication between the two would need to happen over the network, but I would think the existing remote control features could be leveraged for this.

So basically something like the user being able to check a UI box for a given disk in the guest Scanner that says "Enable Passthrough via Local Network / StableBit Cloud+" and then if it can't retrieve SMART from that disk itself it'll first try querying its local peers for that disk and then if that doesn't work it'll try querying the StableBit Cloud+ service (if logged in)?

[servonix]

On 7/15/2026 at 8:38 PM, Shane said:

So basically something like the user being able to check a UI box for a given disk in the guest Scanner that says "Enable Passthrough via Local Network / StableBit Cloud+" and then if it can't retrieve SMART from that disk itself it'll first try querying its local peers for that disk and then if that doesn't work it'll try querying the StableBit Cloud+ service (if logged in)?

Yeah I was thinking something along those lines. Perhaps something a bit more targetted with a global setting to specify if scanner is on either a Hyper-V host or guest, and being able to limit the peering scope between the host and a guest peer list. That way the queries could be targeted to just the host and any guest vm's that have a passthrough disk rather than any machine/vm that has scanner installed on the network. I think it would be fine even if there weren't any UI settings added to scanner if it could all be configured within the config file on the host and guests. I would definitely welcome UI options though if they could be implemented.

Not sure if Alex would actually be willing to do this, but it would be a nice addition for virtualized storage servers using scanner/drivepool and passthrough disks. Pretty much the best of both worlds with fewer drawbacks.