Re: Instance Tradeoff

>I'm going to be putting six or seven databases on the same machine (IBM >RS/6000 w/4 SMP CPU's and AIX running Informix v7.2x). My question is: >what are the tradeoffs between putting each database in its own instance, >vs. putting them all in the same instance. I will need to run reports >from more than one of these databases concurrently (i.e. select ... from >db1:xxx, db2:yyy etc.). A little reflection will make this all clear--it's not as complex as it looks at first blush. Let's see if I can kludge up a quick pro/con list... Databases each in its own instance Pros: If the engine dies on one, it won't take the others down as easily. Easier to track resource usage per database, helps tuning granularity. Cons: Each instance consumes a lot of resources (memory, disk overhead.) Administration is several times as complex as one instance. You have to build synonyms or such to use data from several databases at once--more complexity. Summary: One of the advantages Informix has over some competing products is the ability to run several databases in the same instance. Use it. >Are there any white papers on this in the iiug site? Not that I remember, but there are plenty there. Use the new, faster search facility there to find out! The key word you are looking for is "multiple residency." >I've taken the DBA courses, but this wasn't mentioned. Sure it was. Search for that same key word. It probably wasn't discussed in exhaustive detail, though. The best thing to do would be to just try it and see. If you set up a test system with three or so databases, one per instance, and one instance with the other three, you would very quickly develop a personal feeling for which way suited your application. Have fun playing with it! ______________________________________________________ Clem Akins (aka clema@informix.com) Informix Software, Inc (Standard disclaimers apply) International Technical Support Last seen: Reading 800+ emails accumulated "en conference..."