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?
Example:
LTO-4 drives can write at 120 MiB/s each:
http://en.wikipedia.org/wiki/Linear_Tape-Open
It is then therefore imperative one could sustain this rate to possibly
multiple(!) tape drives on a single system.
Justin.
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