Re: multi-residency vs. single instance, multi-database

Are there any documents out there outlining how multiple residency should be configured (kernel, memory, etc.)? The admin. manuals only show how to setup - not how to configure. Phuoc Ho Bill Ennis wrote: > I believe the biggest issue is the amount of memory on the machine > and the sizes of the databases involved. There is a certain amount > of overhead associated with an engine instance but if you have > databases with any substantial size this overhead becomes a small > percentage. > > A couple of other issues to keep in mind with multiple instances > are: > 1) Tape drives available for backups > 2) Coordinating your backups > 3) Kernal settings for shared memory and semaphores. > > -Bill > > > > > We are getting ready to implement PeopleSoft Financials 7 > > and HRMS 7, phased in over the next year. We are running Informix > > Dynamic Server 7.30.UC3 under HP-UX 11. > > > > Our initial plan was to use Informix' multi-residency capabilities > > to have one database instance for Financials and one database > > instance for HRMS, both running on the same box. Our thought > > was, we could tune the engines separately and any problems > > which required one instance to be brought down would only affect > > that instance and not the other instance. > > > > However, recently we are beginning to question the performance > > of two separate instances compared to creating a single database > > instance with two databases -- one for Financials and one for HRMS. > > We're concerned that the cost of two competing instances for one > > set of resources may require more overhead than creating and tuning > > a single instance. > > > > I'm curious to know people's opinions on this topic (preferably for > > any other PeopleSoft customers, but really anyone who has had > > experience balancing two application databases on a single machine). > > Another alternative is to have each instance running on a separate > > machine, but based on constraints, we will have to run them both > > on a single machine for at least the next year. > > > > Thanks in advance for any ideas/opinions/comments. > > > > Chris Corey > > ccorey@icrr.com > > Database Administrator > > Illinois Central Railroad