On Sun, 21 Jun 2015, Tom Yan wrote:
> I was not saying RAIDs are virtual devices. I just mentioned it
> because I saw things like virtio-blk or zram use blk_queue_io_opt().
>
> I know they all use VPDs, but the main point is whether those hardware
> RAIDs or so are handled by sd_mod, and whether
> "Tom" == Tom Yan writes:
Tom> I know they all use VPDs, but the main point is whether those
Tom> hardware RAIDs or so are handled by sd_mod, and whether those
Tom> "transfer lengths" info are still important when it's just a simple
Tom> drive. To me they look like to be of different nature.
I was not saying RAIDs are virtual devices. I just mentioned it
because I saw things like virtio-blk or zram use blk_queue_io_opt().
I know they all use VPDs, but the main point is whether those hardware
RAIDs or so are handled by sd_mod, and whether those "transfer
lengths" info are still importa
> "Tom" == Tom Yan writes:
Tom> No I put it in the wrong way. What I meant was "sd vs md". For
Tom> example, couldn't the scsi disk driver bind the value it reads from
Tom> the VPD to another variable instead of "optimal i/o size", so that
Tom> this value would be exclusively for RAID (and ot
On 17 June 2015 at 05:28, Martin K. Petersen wrote:
> There are plenty of SSDs that report 4K physical sectors, fwiw.
Oh didn't know that. Wonder if it's yet another garbage info. Though
4k is often a nice value to make use of.
> We gave up on USB-SATA bridges long ago. Their designers appear to
> "Tom" == Tom Yan writes:
Tom> All drives I have are flash drives so none of them reports 4k
Tom> physical sectors.
There are plenty of SSDs that report 4K physical sectors, fwiw.
Tom> The usb-storage driver does not read vpd so it won't be a thing,
Tom> but the the uas driver does.
We ga
On 17 June 2015 at 01:08, Martin K. Petersen wrote:
> The two values have nothing to do with each other. They just happen to
> be the same in your case (65535 is the maximum block count for the WRITE
> SAME(10) command).
>
> Your device sets the transfer length granularity to 1 logical block and
>
