Windows Drivers – How to Re-enable S5WakeOnLan Setting for Realtek NIC Driver

This doesn't really answer your question per se, but as a recommendation software RAID controllers, in my experience, are far less reliable than hardware controllers. If you have the budget for them always opt for a stand-alone card to take the burden of disk IO off of the computer itself.

I can tell you right off the bat that you won't be able to configure the standard Microsoft storage driver with that much granularity.

This is a difficult question, because the Memory Manager and the Cache Manager and the disk system in Windows are all constantly evolving. Advice that you get for Windows 2000 may be irrelevant for Windows 2003 which may be irrelevant for Windows 2008, etc. On top of that, you also have applications such as SQL Server with comprehensive cache managers of their own that may be totally unaffected by or react unpredictably to any changes you make to the OS file system cache. On top of that, this is the sort of functionality that would be taken over by a third party storage driver if you used one. You can assume that the Microsoft-provided one is more generic and therefore less configurable than a driver you might get from Intel or HP that is specialized for their hardware. Many vendor drivers require that Windows write-caching be disabled in order to enable their own write caching, etc.

All that said, I might be able to help you. Since you didn't specify what version of Windows, and like I said, things like registry paths and values and functions can and do totally change between versions of Windows, I'm just going to assume 2008R2/Win7.

From this MS article:

By default, Windows caches file data that is read from disks and written to disks. This implies that read operations read file data from an area in system memory known as the system file cache, rather than from the physical disk. Correspondingly, write operations write file data to the system file cache rather than to the disk, and this type of cache is referred to as a write-back cache. Caching is managed per file object.

Caching occurs under the direction of the cache manager, which operates continuously while Windows is running.

When I alter those checkboxes in the Windows Device Manager for "Enable write caching on the device" and "Turn off Windows write-cache buffer flushing," those changes are reflected in the registry values in HKLM\SYSTEM\CurrentControlSet\Enum\<IDE>\<DiskName>\<Serial Number>\Device Parameters\Disk\CacheIsPowerProtected = 1, etc. The values I placed in brackets are variables.

But I digress. You want to alter the behavior of the file cache. Such as making it flush more or less frequently.

You said you were interested in API calls, which is good, because I think you will be interested in Microsoft Windows Dynamic Cache Service. I think it was written by this guy. Sample source code is included.

A caveat for Win7/2008R2:

The memory management algorithms in Windows 7 and Windows Server 2008 R2 operating systems were updated to address many file caching problems found in previous versions of Windows. There are only certain unique situations when you need to implement this service on computers that are running Windows 7 or Windows Server 2008 R2.

Essentially, you'll be using the SetSystemFileCacheSize() Win32 API function. Check this out:

MinimumFileCacheSize [in]

The minimum size of the file cache, in bytes. The virtual memory manager attempts to keep at least this much memory resident in the system file cache.

To flush the cache, specify (SIZE_T) -1.

This implies you can flush the cache at will, on whatever schedule pleases you.

Good luck!