Curt, Some of these items you're mentioning might be handled by a 3rd party vendor separate from the app server. Check out Peakstone (www.peakstone.com) - they have some interesting stuff. Good luck! John Harby >From: "Smith, Curt H." <[EMAIL PROTECTED]> >Reply-To: A mailing list for Enterprise JavaBeans development ><[EMAIL PROTECTED]> >To: [EMAIL PROTECTED] >Subject: Comparing vendors: scaling + resiliency >Date: Thu, 21 Dec 2000 11:48:45 -0500 > >I'm closer to having to make a buy decission on an architecture >and appserver vendor for a very large scale mission critical system. >100's of boxes, many 1000's of services. > >This must include facilities for control, monitoring and status of the >whole >system. SNMP and what else??? The vendors are weak here! > >I'd like to hear what folks feel about current vendors and possibly what >might be in next releases if anyone's got some info? > >Scaling, my views: Efficient Name Service (NS) and robust client Stub > > - Clustering. > To me, the appserver should support flexible asymetric >clusters. > The cluster should spin up new VMs when load demands. > Weblogic does neither, Gemstone does both, Inprise >supports > asymetric clusters but don't remember if they spin up VMs. > > - Name service > > The best of breed NS that I've seen is in Weblogic server. It >uses a multi-cast group to > keep all NS in a cluster in sync. The worst choice is using >commercial LDAP > directory servers for the local store and LDAP replication to >keep N instances > in sync. Our current appserver uses this architecture and we >hate it for so many > reasons. > > - Client side Stub: > - All vendors support re-bind and re-dispatch on >IOException > > is there differentiation between the vendors? > > - Does anyone support time out on method call?? I.E. an >SLA > and re-dispatch to a different instance when time out >occurs? > To me this is much lighter weight than creating a client >side > transaction context and setting transaction timeout. >The >former > approach would not appreciably increase per-method >latency, > where com.jts.UserTransaction would be a costly >operation > for every method. > > Other vendors stack up? > > - Load balancing. > > - Some vendors use a bulletin board of which services are >busiest > and do method level load balancing. > > I'm not sure I want this all the time?? Another source >of >latency > and bottle neck??? > > - Bind level load balancing. All vendors that support >clustering at least > support this form of load balancing unless they do >method >level balancing. > >Resiliency / fault tolerance (clustered boxes): > > - NS, object activation and system status must not have single >point >of failure. > > Any vendor differentiation here or particularly bad designs?? > > - Client Stub and NS provide re-dispatch of failed (indepotient) >method call. > > I need but haven't found method level timeout. Any vendors >present or future? > > - When service / box fails the NS must be quickly scrubbed of dead >references > > - If singleton services fail they must be restarted else where. > > Any vendor support this? >] > >Thanks for your thoughts and experiences! > >Curt >Architect of our next-gen telephone system. > > >Curt Smith >Z-Tel >email: [EMAIL PROTECTED] >work: 404-237-1166 x182 >FAX: 404-237-1167 > >=========================================================================== >To unsubscribe, send email to [EMAIL PROTECTED] and include in the body >of the message "signoff EJB-INTEREST". For general help, send email to >[EMAIL PROTECTED] and include in the body of the message "help". > _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com =========================================================================== To unsubscribe, send email to [EMAIL PROTECTED] and include in the body of the message "signoff EJB-INTEREST". For general help, send email to [EMAIL PROTECTED] and include in the body of the message "help".
