Hi Bo, Interesting question! We are discussing this too. Some thoughts about it, but no solution or hint.
pro: * more controllers gives you a higher reliability if one or more controllers fail. * more controllers gives you a better load balancing. If the right loadbalancing policy is chosen. remember the sequoia jdbc url contains all controllers and if you do round robin the requests will be distributed to all controllers. contra: * more controllers generate more administration time. Starting, stopping, syncing... * more controllers generate more adminsitrative traffic among all controllers. Remember a sql-insert sent to one controller must be sent to all other controllers. * more group communication and process time. To keep a cluster with 4 nodes running, more group communication and process time for this is needed compared to just 2 nodes. I think it will be 3 time more communication/process time by just doubling the number of controllers. I think the answer is "it depends on". If your application does a lot of sql-insert/updates, i would choose only 2 controllers to minimize sql-insert/update replication and group communication overhead. If your application is mostly using sql-select, i would choose 4 controllers to speed up everything, cause selects are not replicated to any node. btw. If you look at the commercial sequoia software made by continuent, you see, that they only use a 2 controller scenario everywhere. They enhanced this scenario by creating their own group communication protocol "duocom" that only works between 2 nodes. hth stefan Bo Glenn wrote: > Is there anyone, preferably a Sequoia project team member, that can > assist me with this question? We have 10 application servers that are > going to be connected to 2 postgres database servers via Sequoia > controllers and I would like to know if I need to have more than two > controllers. I am interested in hearing arguments for or against having > multiple controllers. Is it better for performance, scalability, are > there known issues/reasons for not having more than two,etc. Please > reply as we need to work on our implementation plan. All help/comments > are appreciated. > > > > Thanks, > > > > Bo > > > > ________________________________ > > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Bo > Glenn > Sent: Wednesday, August 29, 2007 5:47 PM > To: [email protected] > Subject: [Sequoia] using multiple controllers > > > > I would like to know if there is a benefit from using more than two > controllers. We currently have enough hardware to have 4 controllers > with 1 controller per physical machine (4 servers). Our application is > mutli-threaded and does a large number of write and read transactions. > Does it make sense to have more than two physical machines running one > controller each? Is there a performance gain for having more than two > controllers for example 4 controllers to spread the communication to the > backend database servers for JDBC transactions? > > > > I have researched the archives and the documentation and I cannot see an > argument for or against using more than two controllers like the basic > setup uses. It would be great to know if we should leverage our > hardware or if we just need two controllers. > > > > Thanks in advance for any assistance. > > > > Thanks, > > > > Bo > > > > > +----------------------------------------------------------------------+ > | Z1 SecureMail Gateway Info - http://www.zertificon.com | > +----------------------------------------------------------------------+ > | - Die Nachricht war weder verschluesselt noch digital unterschrieben | > +----------------------------------------------------------------------+ > > > > ------------------------------------------------------------------------ > > _______________________________________________ > Sequoia mailing list > [email protected] > https://forge.continuent.org/mailman/listinfo/sequoia -- Zertificon Solutions GmbH Landsberger Allee 117, 10407 Berlin, Germany GF: Herbert Nebel, Dr. Burkhard Wiegel HRB 94059, AG Berlin-Charlottenburg http://www.zertificon.com https://www.globaltrustpoint.com/[EMAIL PROTECTED] +49 (0)30-5900 300-0 (fax -99) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ "Z1 SecureMail" by Zertificon ...the leading server solutions for Secure & Trustable E-Mail Try our Policy controlled S/MIME & OpenPGP & HTTPS Messaging!! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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