This is bit of an odd one. I have a lab server that wasn't getting the Write performance that I would expect. (Based on tests with HDtune) The Controller itself states that Write-Caching is set to enabled. However the OS states that it is not and cannot enable it for the disk.
I also have a 3ware 9550 controller installed with a RAID 5 array and it allows caching to be enabled on the controller and within the OS just fine.
I took an image of the partition on the RAID 10 Array and then blew it away. I recreated the Array making sure that write cache was enabled upon creation. Same Behavior.
The system spec's are as follows:
SAS Raid Controller: Adaptec 4800SAS with attached Battery Backup
Array: 4 x 15K SAS in RAID 10 - 256k clusters
Windows 7 Pro x64
See attached to see the screenshots from the controller and the OS. I would deduce that enabling and controlling write-caching on the controller would then prevent one from doing the same within the OS. But as I said this is not the case on the 3Ware (LSI) controller.
So shouldn't I be able to modify the write-caching policy of the Disk from the OS? Or is this specific to to Vendor / Driver?