Forum Discussion
W10-1903 UNC path failing 0x80070043
Hi everyone. We got access to the Dell KB and see the issue in Dell/EMCs 'Unity' CIFS implementation.
From the DELL EMC KB attached to thread (below), the Unity SMB Server implementation is failing on the "SMB2_NETNAME_CONTEXT" and "SMB2_COMPRESSION_CAPABILITIES" we added in 1903. These were changes designed to add some new capabilities to SMB; we make some variant of these at most OS releases. If an SMB/CIFS server doesn't recognize capabilities, it should ignore them, not fail. Otherwise Dell would have to update their SMB implementation every time we released a new SMB capability that didn't also include a protocol dialect revision (like "SMB 3.1.2"), forever and ever.
Error Messages in the Unity c4_safe_ktrace.log:
sade:SMB: 3:[nas_serverx] Unrecognized SMB2 negotiate context type 0003
sade:SMB: 3:[nas_serverx] Unrecognized SMB2 negotiate context type 0003SMB client sends the compression context before the netname context, so the server encounters the compression context first. The Unity server would probably encounter the same problem with the netname context. Instead of failing when their SMB Server version doesn't support more advanced capabilities, it should be ignoring those capabilities. This is what Windows and other 3rd party SMB products do.
kurgan thanks for opening this techcommunity item, I'm sorry I didn't see it until now.
Ned Pyle | Principal Program Manager, MS | @nerdpyle on twitter
You should make a SR to Dell EMC about Compellent if you haven't done it yet.
Seems like Dell EMC are working to address it; at least on the Unity platform.
From the kb:
"Dell EMC is investigating an enhancement to address this issue. Dell EMC will update customers once more information on this enhancement becomes available to customers under current Dell EMC maintenance contracts."
Case opened with them on the Compellent side. To hear it from the rep I spoke with they just learned about this last week. For anyone else who using the FluidFS compellent setup the only current solution is to uncheck the v3 SMB option on the FluidFS.
If anyone wanted the case toe reference,
SR 991311217
The engineering team at EMC are working on providing a resolution or hotfix in the next patch.
I've also got permission from EMC to post their official document about Unity and Windows 1903 here.
The .pdf includes instructions for the workaround to downgrade to 3.0.2
Please see the attached document.
- From Dell on the Compellent end of things as of 6/2/2019
"I’m following up on our case regarding the Windows 10 1903 update and SMB share access. At this time, our development team is still testing possible solutions. They are also investigating potential client-side workarounds. However, we currently only have the workaround of disabling SMBv3 on the FS itself."
