disk write buffering not disabled by FILE_FLAG_NO_BUFFERING+FILE_FLAG_WRITE_THROUGH

[Jeff-01]

We're finding that despite using FILE_FLAG_NO_BUFFERING and FILE_FLAG_WRITE_THROUGH that we still lose disk writes which have completed if there is a power failure unless we also go into Device Manager and disable write caching - there does not seem to be any way to disable write caching in software despite the documentation (https://docs.microsoft.com/en-us/windows/win32/fileio/file-caching). I believe this is why the Oracle says that write caching must be disabled in the device manager to ensure data integrity:
https://docs.oracle.com/en/database/oracle/oracle-database/19/cwwin/disabling-write-caching.html#GUID-17FF487A-61E0-4A91-82C4-F8AC9DD1A389

Unfortunately it is very hard to get people to do this - we really need some way to disable write caching on files from software.

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[KalleOlaviNiemitalo]

These have some information about caching in disk drives, but I don't know whether it is up to date:

• Deploying Transactional NTFS - Win32 apps | Microsoft Docs (May 2018)

  Starting in Vista, Windows supports the FUA flag only for SCSI and Fiber Channel disks.

  You can disable a disk's write caching by issuing the IOCTL_DISK_SET_CACHE_INFORMATION control code to the disk.

• Hyper-V storage: Caching layers and implications for data consistency (February 2013)

• persist hard link — OSR (April 2012)

• Ordering of I/O requests — OSR (November 2004)