Re: RAC Interconnect

  • From: "Anand Rao" <panandrao@xxxxxxxxx>
  • To: ax.mount@xxxxxxxxx
  • Date: Fri, 24 Nov 2006 11:13:27 +0530

Alex,

It would not a good idea to recommend a single interconnect based on just
the user count.

i could have 5000 users, each generating only 10K of inter-node traffic. so,
that about 50MB/s. so, user count is not the correct yardstick.

you have to measure the interconnect traffic generated by each database
(from the application) and then decide. for testing, don't run both the
databases together, you won't see a "per application usage".

measure the traffic generated from each database with the application going
full throttle. if you cannot simulate that, then you have no choice but to
run the production system with both databases and then measure.

so, you could do with just 1 or maybe 2 but load-balancing between them will
be a Veritas/Solaris responsibility. 10g RAC CRS may allow load-balancing
over the VIP, not sure.
Gopal?

guess you are on Solaris 10, so the netstat command should help to capture
the interconnect traffic. i guess there is another command introduced in
Solaris 10. I haven't used it, but i hope the Solaris Management Suite will
provide some good graphical detail of interconnect traffic.

you will get ~90-95 MB/s sustained, depending on the card and the latency. i
don't know how good LLT is compared to UDP. i would suggest UDP (life is
easier) with some good tuning of UDP buffers at the OS layer. You should
also look at tuning the TCP buffers, though it is not directly related to
the interconnect.

hope this helps.

thanks
anand


On 24/11/06, amonte <ax.mount@xxxxxxxxx> wrote:

Hi

As mentioned a few days ago I am installing a RAC with Verits SFRAC on
Solaris 10.

I have to create 2 databases to for this RAC implementation. Both will
share a single Gigabit connection (using Veritas GAB/LLT). The databases
will be OLTP supporting around 400 users each. No chance to put them in same
database. I was wondering if a single interconnect would be enough?

TIA

Alex


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