On 6/29/23 00:54, Bart Van Assche wrote:
On 6/26/23 13:35, Daniel Rozsnyó wrote:
There are some drives, or more precisely - normal drives with a custom firmware, that simply reject a regular Write - likely as not being good enough for the intended high-rel application - which I can understand, but even after reformatting the drive to no-PI and going to "poor" 512B sector
size, they still refuse to do an easy Write operation. I had verified that by using the sg_write_verify (that uses an ioctl) I can really write data to these drives. The reading path is working okay and both dd and hdparm works at expected speeds.
To me the above sounds like the drive firmware is broken. Please fix the drive firmware and make sure that WRITE commands are accepted.
It is not broken - it is by design. Or call it a feature (although it would be nice to have a configurable flag that controls the rejection on the drive side).
Same principle as is in place for more than a decade with server BIOSes (eg from Supermicro) insisting on using ECC equipped memory - otherwise a specific POST code happens and the machine wont start, even that non-ECC one would be fine on the given CPU/IMC (and indeed does run on other brands).
(IRONY ON) If your approach is so "simple" - could you just "simply" ban from Linux a complete lineup of 2 major hard drive vendors (Seagate, HGST), until they do fix my particular firmware? Sure we do not want to support these incompetent drive makers that ship drives with a potentially "broken"
fw. (IRONY OFF)
I could contact the vendors, but the firmware is not made for me - so I have naturally no control over it. And the drive does not accept a firmware flash to its own generic firmware family (now that I would say that went a bit too far).
So could we at least find any reference from a T10 committee - how they classify the WRITE command?
- is it being a mandatory operation? Is that written in any SPC/SBC spec?
Oh - I did it: https://www.t10.org/lists/op-alph.htm and you wont be happy:
The WRITE(10) is *OPTIONAL* for a Direct Access Block Device (SBC-4)
- so nope, the firmware which has no WRITE command is NOT broken according to the T10 standards.
Lets get back to the original request/question then. What is the proper approach to handle such command variation?
Daniel
