Request for registry tweak to adjust SMB CA lock limits

Hi Oluver Koskinen,

you are encountering File Lock Exceeded errors on your Scale-Out File Server. This is not caused by an SMB Continuous Availability lock limit, as the SMB protocol does not enforce a configurable lock ceiling that generates this specific message. Instead, this error originates from the Microsoft Jet or Access Connectivity Engine on your client machines when a high-density transaction attempts to open more than the default 9,500 concurrent file locks.

To resolve this, you must modify the registry on the client machines executing the database queries, not the SoFS cluster nodes. Open the Registry Editor on the affected client and navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\16.0\Access Connectivity Engine\Engines\ACE for modern environments, or HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Jet\4.0\Engines\Jet 4.0 for legacy 32-bit applications. Find the MaxLocksPerFile entry, double-click it, select the Decimal base, and increase the value to 50000 or a number large enough to accommodate your specific workload density. Restart the client application to finalize the configuration, allowing your database engine to process massive transaction locks over the SMB share without crashing.

Hope this answer has brought you some useful information. If it did, please hit “accept answer”. Should you have any questions, feel free to leave a comment.

VPHAN