NetServer and Windows SMBv2 Caching

Cause

Caution: This document directs you to a Microsoft document that discusses making changes to the Windows registry with the registry editor, regedit. Before using this tool to make any changes to your registry, back it up, and make certain you understand how to restore the registry if a problem occurs. Consult Microsoft's knowledge base and help system for information on using regedit, regedt32 registry editor programs. IBM is not responsible for any issues caused by changes made to a PC registry. If in doubt, always consult Microsoft before making such changes.

NetServer and the underlying IBM i file systems do not support the Change Notify API. That means that (among other things) the server does not have a mechanism to asynchronously poke the client cache to force a refresh of information. Any delay in the client seeing a new file on the NetServer likely aligns with the cache expiration and refresh on the client.

A Microsoft Technet article called 'SMB2 Client Redirector Caches Explained' contains documentation on Windows client caches that may cause a variety of errors, particularly 'file not found'.

The article is currently found at:

https://technet.microsoft.com/library/ff686200(ws.10).aspx

Note: This is a Microsoft article and Microsoft could change the URL at any time. If this happens, a search by the article name might be necessary in order to find the article..

IBM Support has seen situations where changing the DirectoryCacheLifetime (described in the Microsoft article) to a shorter time (for example, <= 3) has fixed the issue.

Alternatively, disabling the SMB2 Directory Cache (in the potential absence of the DirectoryCacheLifetime value) should also resolve the issue.

These are Microsoft settings, so anyone considering a change to them should review the Microsoft Technet article 'SMB2 Client Redirector Caches Explained', which is referenced above.

There is also a Microsoft hotfix for Windows 7 and Windows Server 2008 RC2 where a "STATUS_OBJECT_NAME_NOT_FOUND" (equivalent to 'file not found') error message is received when attempting to open a newly created file in a shared folder. The fix can be found by searching online for: Hotfix 2646563