Re: File Systems Compared

llonergan@greenplum.com

From: "Luke Lonergan" <llonergan@greenplum.com>
To: "Brian Hurt" <bhurt@janestcapital.com>
Cc: pgsql-performance@postgresql.org
Date: 2006-12-06T17:40:25Z
Lists: pgsql-performance
Brian,

On 12/6/06 8:40 AM, "Brian Hurt" <bhurt@janestcapital.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