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How To: Getting SMART data from Hyper-V


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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


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?




Edited by drashna
Instructions for Hyper-V
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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".

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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.)

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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."

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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.

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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.

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