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Re: File Systems Compared


  • From: Brian Hurt <bhurt(at)janestcapital(dot)com>
  • To: Luke Lonergan <llonergan(at)greenplum(dot)com>
  • Cc: pgsql-performance(at)postgresql(dot)org
  • Subject: Re: File Systems Compared
  • Date: Wed, 06 Dec 2006 15:24:09 -0500
  • Message-id: <457726E9(dot)50607(at)janestcapital(dot)com>

Luke Lonergan wrote:
Brian,

On 12/6/06 8:40 AM, "Brian Hurt" <bhurt(at)janestcapital(dot)com> wrote:

  
But actually looking things up, I see that PCI-Express has a theoretical 8
Gbit/sec, or about 800Mbyte/sec. It's PCI-X that's 533 MByte/sec.  So there's
still some headroom available there.
    

See here for the official specifications of both:
  http://www.pcisig.com/specifications/pcix_20/

Note that PCI-X version 1.0 at 133MHz runs at 1GB/s.  It's a parallel bus,
64 bits wide (8 bytes) and runs at 133MHz, so 8 x 133 ~= 1 gigabyte/second.

PCI Express with 16 lanes (PCIe x16) can transfer data at 4GB/s.  The Arecas
use (PCIe x8, see here:
http://www.areca.com.tw/products/html/pcie-sata.htm), so they can do 2GB/s.

- Luke 




  
Thanks.  I stand corrected (again).

Brian



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