Brian,

On 12/6/06 8:02 AM, "Brian Hurt" <bhurt@janestcapital.com> wrote:

> These numbers are close enough to bus-saturation rates

PCIX is 1GB/s + and the memory architecture is 20GB/s+, though each CPU is
likely to obtain only 2-3GB/s.

We routinely achieve 1GB/s I/O rate on two 3Ware adapters and 2GB/s on the
Sun X4500 with ZFS.

> advise new people setting up systems to go this route over spending
> money on some fancy storage area network solution

People buy SANs for interesting reasons, some of them having to do with the
manageability features of high end SANs. I've heard it said in those cases
that "performance doesn't matter much".

As you suggest, database replication provides one of those features, and
Solaris ZFS has many of the data management features found in high end SANs.
Perhaps we can get the best of both?

In the end, I think SAN vs. server storage is a religious battle.

- Luke



---------------------------(end of broadcast)---------------------------
TIP 5: don't forget to increase your free space map settings

> As you suggest, database replication provides one of those features, and
> Solaris ZFS has many of the data management features found in high end SANs.
> Perhaps we can get the best of both?
>
> In the end, I think SAN vs. server storage is a religious battle.

I agree. I have many people that want to purchase a SAN because someone
told them that is what they need... Yet they can spend 20% of the cost
on two external arrays and get incredible performance...

We are seeing great numbers from the following config:

(2) HP MS 30s (loaded) dual bus
(2) HP 6402, one connected to each MSA.

The performance for the money is incredible.

Sincerely,

Joshua D. Drake



>
> - Luke
>
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 5: don't forget to increase your free space map settings
>
--

=== The PostgreSQL Company: Command Prompt, Inc. ===
Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240
Providing the most comprehensive PostgreSQL solutions since 1997
http://www.commandprompt.com/

Donate to the PostgreSQL Project: http://www.postgresql.org/about/donate




---------------------------(end of broadcast)---------------------------
TIP 7: You can help support the PostgreSQL project by donating at

http://www.postgresql.org/about/donate

Luke Lonergan wrote:

>Brian,
>
>On 12/6/06 8:02 AM, "Brian Hurt" <bhurt@janestcapital.com> wrote:
>
>
>
>>These numbers are close enough to bus-saturation rates
>>
>>
>
>PCIX is 1GB/s + and the memory architecture is 20GB/s+, though each CPU is
>likely to obtain only 2-3GB/s.
>
>We routinely achieve 1GB/s I/O rate on two 3Ware adapters and 2GB/s on the
>Sun X4500 with ZFS.
>
>
>
For some reason I'd got it stuck in my head that PCI-Express maxed out
at a theoretical 533 MByte/sec- at which point, getting 480 MByte/sec
across it is pretty dang good. 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.

Brian

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



---------------------------(end of broadcast)---------------------------
TIP 2: Don't 'kill -9' the postmaster

Luke Lonergan wrote:

>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
>
>
>
>
>
>
Thanks. I stand corrected (again).

Brian