On Mar 1, 2010, at 1:31 AM, Abdullah Al-Dahlawi wrote:> Greeting ALL
>
> Can someone explain to me why I was successfully able issue (through
application) an I/Os of 128K each (monitored by DTrace) while my Maxphys=56K
only ??????
>
> My understanding is that Maxphys is the max I/O size that the storage
device can handle for a single I/O, it has been well documented that if and
application issued an I/O larger than Maxphys, it would be break down to
multiple I/O of Maxphys sizes.
>
> But in my case , this did not happen ????????
>
> Any logical explanation for my case ?
>
> I am using an Intel based machine with the latest release of Opensolaris
maxphys is used by UFS, but not by ZFS.
maxphys is also used for the sd driver, but not for x86 architectures where the
equivalent
limit is set to 256KB. I''ll bet that you are running on an x86 system
:-)
-- richard
ZFS storage and performance consulting at http://www.RichardElling.com
ZFS training on deduplication, NexentaStor, and NAS performance
http://nexenta-atlanta.eventbrite.com (March 16-18, 2010)