On Thu, Dec 17, 2009 at 12:46 PM, Kenneth Westerback
<kwesterback@gmail.com> wrote:
quoted text
> On Wed, Dec 16, 2009 at 7:12 PM, Marco Peereboom <slash@peereboom.us>
wrote:
quoted text
>> yes
>>
>> On Thu, Dec 17, 2009 at 12:30:46AM +0100, Robert wrote:
>>> Hi,
>>>
>>> I just read [1,2] that Western Digital (and probably others) will start
>>> to sell disks with an internal block size of 4KB instead of 512 byte.
>>>
>>> The article mentions that this might lead to a considerable performance
>>> impact if the  logical partition alignment is not in sync with the
>>> physical one ("e.g. if partitions starts at sector 63 wich is not a
>>> multiple of 4KB" [1]):
>>> "If a block of 4KB should be written, which is (logically) aligned, but
>>> physically in fact 2 sectors, then both physical sectors will need to be
>>> read, partially modified and then written back which leads to a serious
>>> performance hit." [1]
>>>
>>> Any comments from someone who has a good knowledge of this area? Will
>>> this affect OpenBSD?
>>>
>>> regards,
>>> Robert
>>>
>>> [1] (german)
>>>
>
http://www.heise.de/newsticker/meldung/Festplatten-mit-4-KByte-Sektorgroesse-
quoted text
> 887759.html
>>> [2] http://www.wdc.com/wdproducts/library/whitepapers/en/2579-771430.pdf
>>
>>
>
> 4K sectors themselves should work ok as we already do that for ffs on
> CD media. Which works the last I checked. Ensuring alignment on blocks
> will have to be checked. It sounds like some should donate a few of
> these 4K devices to the project so we can fix any issues asap.
>
> .... Ken
>
>

I'm looking into the possibility of modifying QEMU for testing this.
Not sure how close such things would be to reality, but it's worth a
look in any case and would drop the cost of development significantly.

--
Aaron Mason - Programmer, open source addict
I've taken my software vows - for beta or for worse