Hi Martin, I had assumed that the VPD values for the LUNs were valid, and hadn't even thought to check if they were standards-compliant. Based on the SBC descriptions, it is clear that you are correct and this is an issue with the storage not reporting a proper max_ws_blocks. At least now I have enough details to demonstrate to NetApp that this is an issue on their side, and also have the relevant details from SBC. Thank you once again for your help in understanding the underlying technical issues responsible for the WS UNMAP failures in my environment. I really appreciate you taking the time to respond, especially as this didn't turn out to be an issue with kernel code at all. -David
