Oracle FAQ Your Portal to the Oracle Knowledge Grid

Home -> Community -> Mailing Lists -> Oracle-L -> RE: RAC Interconnect

RE: RAC Interconnect

From: Hameed, Amir <>
Date: Fri, 24 Nov 2006 01:08:03 -0500
Message-ID: <>

I have worked with LLT for over two years with DBE/AC 3.5 for 9i RAC and found no issues what-so-ever with it (LLT). It is a very reliable protocol, proprietary though, but reliable. The LMX driver does the multiplexing and de-multiplexing for LLT, so if you are using multiple interconnects, your traffic will be load-balanced without you doing/configuring anything special. I have not really seen any clear statement from Oracle for de-supporting LLT in the future even though they have been emphasizing on using UDP, which is very typical of Oracle.

[] On Behalf Of Anand Rao

	Sent: Friday, November 24, 2006 12:54 AM
	Subject: Re: RAC Interconnect
	"10g RAC CRS may allow load-balancing over the VIP".
	not talking of VIP here, typo error. load balancing is
definitely possible in 10g RAC. pls ignore the VIP comment.         

        also, i've got a whiff of the rumour that LLT could be de-supported by Oracle, so in any case, you are better off with UDP in terms of performance and reliability.         

	On 24/11/06, Anand Rao <> wrote: 

		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.


                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.                 

		On 24/11/06, amonte <
<> > wrote:


                        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                          

Received on Fri Nov 24 2006 - 00:08:03 CST

Original text of this message