'SMB direct' disable on Windows 10 implications

Question

Dear Storage/Windows experts,

Here's the environment.

• Our users are using Windows 7/Windows Server 2008 R2 to connect to group/project shares on NetApp (Only SMBv1 enabled).
• Users home drive/profiles are also on NetApp.
• We are migrating to another Storage Platform, in addition to migrating all users to Windows 10
• Will be using SMBv2 on Win10 and on new Storage Platform.

Problem is that we might have some users, who are migrated to Win10(SMBv2) but need to connect to NetApp shares(SMBv1).

To resolve this,

• We decided to enable SMBv1(until we are done with Storage migration), on all Win10 machines so that clients can use both new Storage and NetApp.
• Found out that we need to disable 'SMB Direct' feature in Win10 for this to happen.

Found couple of good documents..

https://docs.microsoft.com/en-us/windows-server/storage/file-server/smb-direct

https://www.windowscentral.com/how-access-files-network-devices-using-smbv1-windows-10

Question is, has anyone already been through disabling SMB Direct AND/OR has seen any noticeable consequences? Really appreciate the inputs.

Answer 1

If you're only using SMBv2, not SMBv3 then disabling SMB Direct will have no consequences as it's limited to version 3. If your new storage platform supports SMB Direct, you'll see increased CPU usage on the client and file server as well as potentially lower throughput with SMB Direct disabled, relative to what you would see if you had it enabled. Depending on the number of clients you have connecting to the same server, this may significantly degrade performance. However, if your file server hardware doesn't support RDMA then none of this matters as SMB Direct won't work ever.

You may want to consider changing all clients from SMB version 1 to version 2 as there are significant performance enhancements in v2 over v1, as well as major security enhancements. Windows 7 supports v2, as does Server 2008R2. On Tap 8+ supports v2 and 3, though you're not likely to see the same performance increases that you would if you were using these features on a native Windows file server.