On Mon, Jun 07, 2010 at 09:41:29PM +0300, Boaz Harrosh wrote: > On 06/07/2010 09:29 PM, J. Bruce Fields wrote: > >>> On 06/07/2010 07:07 PM, Boaz Harrosh wrote: > >>>> I did not yet publish the Document. It's stuck behind my dis-talent for > >>>> writing and the pnfs bugs de jur. > > > > Untalented writing we can fix, as long as the details are there! > > > >>>> > >>>> Basically all machines: > >>>> - connected by a 1 GBit link. > >>>> - All clients doing a dd write of 8GB file from /dev/zero > >>>> - 3of8 is the special raid-groups arrangement of exofs && objlayout > >>>> where out of 8 devices each file is striped over 3 devices in a > >>>> round robin fashion. (*With a small dirty trick) > > > > Random stupid questions: > > > > - why do you think the 3of8 arrangement is scaling better than > > the 8of8? > > It's a know problem with a network storage cluster. What happens is > that with 8of8 all the clients exercise all of the nodes at the same > time so they are clashing on the network. OK, so if two clients are both trying to send a stripe of data to the same OSD data at the same time, absent a switch that could somehow afford to queue up a full stripe-unit's worth of data, packets get lost? (Also, out of curiosity: do you know of any papers or documentation that describe that problem in more detail?) --b. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
