QuickPost – setting Storage Sense cloud content dehydration on Server 2019

Storage Sense is really useful for helping to keep OneDrive cache down. I wrote an article a while ago explaining how you can use Storage Sense in conjunction with Files On Demand to aggressively trim the OneDrive cache and reduce the load both on your storage and your RDSH servers.

Essentially, Storage Sense has a setting to “dehydrate” what it calls “cloud content” (which to all intents and purposes means OneDrive cache). “Dehydration” is removing the cached copy and falling back to downloading the cloud-stored copy when it is opened. Simple, eh?

GPOs

On the surface, it would seem yes. On Windows 10, you simply configure the Storage Sense GPOs and away you go. For a comprehensive list of the required GPOs, see the article linked in the introduction.

However – when doing this on Server 2019 (as you need Server 2019 to support Storage Sense and Files On Demand), be prepared for a nasty shock, because the GPOs actually don’t work.

You can see the Storage Sense settings by going into Settings | System | Storage (interesting side note – you can’t see System in the Settings app when you’re logged on via pure RDP), so it obviously works with Server 2019.

Interestingly, at the bottom of that screen, the option for “dehydrate cloud content” doesn’t appear – not until the user actually logs into OneDrive. Once OneDrive is configured and active, it appears in the Settings screen.

But as mentioned, none of these settings take any notice of the configured GPOs and would have to be set up by the user themselves. Which is not great, given that the default is to set the cloud dehydration threshold to “Never”.

Registry settings

Given that the user can actually configure these settings themselves, though, that means that there are bound to be Registry values we can leverage to preset them.

Of course, it would be too much to ask for Microsoft to make the Registry values sensible and predictable. Here I was expecting the value to turn on Storage Sense to be something like “StorageSenseEnabled” with a DWORD of 1 for on and 0 for off, but no, that would be too easy.

Storage Sense base settings

The main Storage Sense settings are stored in the following key:-

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\StorageSense\Parameters\StoragePolicy

They’re numeric values for each setting – and some of the settings have two values rather than one. Yes, that makes perfect sense (that’s with a heavy dousing of sarcasm for those who don’t know me). They map as follows, best I can tell:-

Now, there are other values in this Registry key, but don’t touch those – I have no idea what they do.

Cloud dehydration settings

The settings for cloud content dehydration are another kettle of fish. Oh yes.

These sit in a subkey of HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\StorageSense\Parameters\StoragePolicy, but the name of the subkey goes by the following format:-

OneDrive![USERSID]!Business1|[ONEDRIVEGUID]

Bear in mind that if you have users with multiple OneDrive accounts, you may see subfolders listed as Business1, Business2, etc.

So for mine, which only has one account, it looks like this

This key contains two values which map as below:-

Of course, the real trick is getting the user’s SID and the GUID value so that you can add these into the path to set these last Registry values. The SID is easy enough to pull, but the OneDrive GUID (or the Provider, to give it the correct name) can be found elsewhere in the Registry, most notably at

HKEY_CURRENT_USER\Software\SyncEngines\Providers\OneDrive

Getting the user SID can be done easily with PowerShell or even by parsing the whoami command (both shown below)

for /f “skip=5 tokens=2 delims= ” %%a in (‘whoami /user /fo list’) do set USERSID=%%a

$USERSID = [System.Security.Principal.WindowsIdentity]::GetCurrent().User.Value

Alternatively, don’t forget that in Group Policy Preferences if you press F3 you get a list of available GPP variables – one of which is the user’s SID (%LogonUserSid%)

The GUID value (or the Provider as it should be called) is a little trickier because it is unique to each user. You will need to read in the Registry key mentioned above and set it as a variable somehow.

If you want something pre-rolled, then see Kasper Johansen’s GitHub for a script that you can run at logon to set all these values nicely for you – linked here

Deploying

Once you’ve worked out how you want to skin this – whether it’s running Kasper’s script or using some form of GPP or WEM to inject the required Registry settings, you should now be able to deploy Storage Sense settings correctly onto Server 2019 RDSH instances.

Grabbing that user-specific Provider GUID from the Registry at HKEY_CURRENT_USER\Software\SyncEngines\Providers\OneDrive is the key part. Kasper’s script is probably the easiest way to do it – you can either use it in full or do what I did and simply hijack the required line and set a user variable (I called it %OneDriveProvider% and set it via a PowerShell logon script). Dependent on your environment, there are probably loads of ways you could achieve this.

Once I’d done that then a simple injection of GPP variable for the user SID made it good. You can then simply put the variables into the path for the last two Registry items as below.

Once we’ve done that and refreshed Group Policy, all of these Storage Sense settings should be preset for the user when they log into OneDrive.

Summary

This is a real pain in the backside. Microsoft, please make Server 2019 respect the Storage Sense GPOs! Until then, this should get you by.

Kudos obviously due to Kasper Johansen for identifying and rectifying this before I even realized it was a problem.