I am not sure if this warning is a reason for concern or a reason to add more drives as suggested: Storage Spaces Warning

I have this setup as a 2-way mirror, so that both drives should hold identical data. Both of them are of exactly the same size and both have the same 30% of space free. I therefore do not understand why is it telling me to add more drives, when in fact there is still 30% free space left and I am using a simple mirror for identically-size drives with no parity or other advanced options?

Using Windows 10 10586.


It tells you to add two instead of one, that's why two.

Default threshold for this warning is 70%. You could try changing it via

Set-StoragePool -FriendlyName "SS1" -ThinProvisioningAlertThresholds X

in Powershell, where X is percentage of taken space for alert to occur. Documentation here.

  • I understand that, but why is it complaining for a 2-way mirror? I mean I understand why it would complain at 70% full with some other setup (different size disks, parity, etc.), but with this setup, if it is indeed a mirror, as they claim, there should be 30% free space on both drives and no reason to complain about anything. That's what I don't get and what worries me. Is this 70% thing for all storage spaces just a sloppy design decision? – Fit Nerd Jan 28 '17 at 13:35

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