Windows 10 used as a server

Topics: General
Aug 1, 2016 at 10:27 PM
We recently encountered a bizarre issue running our VFP application software at a small client site, who had just installed a Windows 10 computer as their entry-level "server". After a couple of weeks (which included loaning them one of our machines that was dual-boot Win 7 Pro & 10 Pro) as a temporary substitute server to help diagnose the cause), we think we have finally cracked it.

The symptoms were that 'simultaneous' (within a minute or so. rather than milliseconds) write activity by two users, trashed indexes (mixing up lines from different orders and invoices). This occurred only when running Windows 10 as the server - no problems at all when running Windows 7. It occurred both on their 'server' (running Windows 10 Home - yes, they went really cheap), and ours (running Windows 10 Pro).

Cause: It seemed to be caused by Write-caching issues on the server hard drive.

Solution: Disabling Write-Caching on the server hard drive seemed to solve the Win10 problem. (See Device Manager > Disk Drives > Policies)

Discussion: I am mystified as to why Windows 7 works fine with Write-Caching enabled, but Windows 10 doesn't. I always understood this was an internal configuration setting for the device itself. But the fact that Write-caching works in Win7 but not Win10 suggests that this is instead a setting for the Windows device driver, and there is a bug in the Win10 driver (or system layers above this), that doesn't serve cached writes correctly to other users. It seems that Win10 serves other users the out-of-date original CDX image from the hard drive. In due course, their writes back to the CDX are incompatible with other users, and the CDX gets trashed. Has anyone else encountered this, or can anyone shed light on it?