On Sun, Jun 01, 2008 at 07:26:09AM -0400, Justin Piszcz wrote: > > > On Sun, 1 Jun 2008, Justin Piszcz wrote: > > > > >On Sun, 1 Jun 2008, Justin Piszcz wrote: > > > >>I have 12 enterprise-class seagate 1TiB disks on a 965 desktop board and > >>it appears I have hit the limit, if I were able to get the maximum speed > >>of all drives, ~70MiB/avg * 12 = 840MiB/s but it seems to stop aound 774 > >>MiB/s (currently running badblocks on all drives).. > > > >Small correction, they are 7200.11 Seagate Desktop Drives (ST31000340AS), > >not enterprise drives: > > > >http://www.seagate.com/ww/v/index.jsp?vgnextoid=0732f141e7f43110VgnVCM100000f5ee0a0aRCRD > >http://www.newegg.com/Product/Product.aspx?Item=N82E16822148274 > > > > > > http://www.intel.com/products/chipsets/g965/diagram.jpg > > Basically it appears I am hammering the southbridge as for this board the > PCI-e (x1) slots also traverse through the southbridge. > > 6_SATA -> G965 ICH8 > 3_PCI-e -> G965 ICH8 > > >From which has to ship that data across the DMI (2GB) link to the > northbridge. > > If one utilized a 12, 16 or 24 port raid card (but used SW RAID) on the > x16 slot on the northbridge itself, would this barrier exist as the: > GMCH<->CPU is (8.5GB/s)..? > > Also on the X38 and X48 the speed increases slightly: > http://www.intel.com/products/chipsets/X38/X38_Block_Diagram.jpg (10.6GB/s) > http://www.intel.com/products/chipsets/x48/x48_block_diagram.jpg (12.8GB/s) > > If one asks why would one need such speed? It looks like graphic games are pushing the technologies to their limits, which is good for us. I have bought X38 motherboards for 10 Gbps experimentations, and this chipset is perfectly capable of feeding two Myri10GE NICs (20 Gbps total). This is 2.5 GB/s, not counting overhead. So I/O bandwidth is a premium requirement today. Other chipsets I have tested (945 and 965) were very poor (about 4.7 and 6.5 Gbps respectively if my memory serves me right). Willy -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
