Re: 2 Instances, 1 machine VS 1 Instance 2 databases

Keith L Morris wrote: > > Greetings, > > The current job I find myself in was setup with 2 INFORMIX instances > each with one database. (On the same machine.) > > We have applicattions that link to both concurrently and do work. > > I would THINK that ONE instance with TWO databases (giving the one > instance all the CPU, DISK etc that BOTH originally had) would end up > being FASTER than the current scenario. > This all depends on the activity of each DB server. However, running two instances on a single box will definitely use up more memory and CPU cycles. I would suggest that you have the two databases in one instance of Informix and just allocate more resources (buffers, logs, virtual segments, etc.) in the Informix configuration. With that you can create the database on a separate set of dbspaces so as to balance the I/O. > Anybody have ANY experience with this kind of situation? > > (The current project lead thinks the database engine is the > bottleneck....... I'm thinking that it's the application code AND things > like this architecture. Although in defense of the architecture... > I think the original developers thought they may some day put each > instance on a DIFFERENT machine. But NOT SO.) > One benefit of having an architecture like the one you have is that is something goes wrong with the first instance it will not affect the apps running in the second instance. You should look at the CPU utilization of the two instances if both of them are eating a lot of cycles, if it is you are probably better off in having the two databases share an instance of Informix. > We've recently started using the STATEMENT CACHE and had a major > increase... although we had to "LOOP OUT" a lot of the SQL code because > it was written in such a manner that it was NOT cacheable. (I will be > fixing that SOON.) > > Anyway.... any real world or benchmark info on the 2 instace - 1 db each > VS 1 instance 2 db would be GREATLY appreciated. > > (I have not seen any documentation concerning this in the Informix > Performance manual. Although I WILL be perusing the manuals this > afternoon.) > > Thanks, > Keith L Morris > keith.l.morris@wcom.com