On 08/07/2014 06:21 PM, Karel Zak wrote: <> > > fdisk uses physical sector size or minimal I/O size (greater value wins) > OK >> I was trying to play with the heads, sectors, cylinders; values but none I tried > > don't play with CHS, that's waste of time and it's completely ignored > by fdisk by default > >> would cause an alignment of 4k, not even of the first partition start. >> >> Please advise what I can do? > > IMHO you're right with your patch (alignment offset is IMHO bad way). > It's all (brd) about pages, is there any reason to use something else > for I/O limits? > > It would be also nice to set minimal and optimal io size, zero values > in this case means (for userspace) that the device does not provide > any I/O information to system. It's normal for old hw disks and then > we use some built-in defaults, but I don't see a reason to do the > same for virtual devices. > Hi Ross I have by now read the all code, and Karel also confirms this from fdisk side. The best for us is the use of "physical sector size" but with our "minimal I/O size" set to 512. The later has actual bad effects in the Kernel code itself. But the "physical sector size" has no effect on Kernel code, and actually has a very good affect on fdisk which now works the way we would like it. Please send your review-by so Jens can pick these up for mainline > Karel > Thanks Boaz -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
