From: Luke Lonergan <llonergan@greenplum.com>
To: Brian Hurt <bhurt@janestcapital.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: File Systems Compared
Date: Wed, 06 Dec 2006 09:40:25 -0800
Message-ID: <C19C4089.14E0D%llonergan@greenplum.com> (raw)
In-Reply-To: <4576F266.9040205@janestcapital.com>
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
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To: pgsql-performance@postgresql.org
Cc: llonergan@greenplum.com, bhurt@janestcapital.com
Subject: Re: File Systems Compared
In-Reply-To: <C19C4089.14E0D%llonergan@greenplum.com>
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