memory increase
Hi all, I'm not an Informix DBA but I want to check if what our DBA told me about configuration on Informix after increasing memory on our AIX 4.3.3 box is true. The version of Informix is 7.31UC4, I think. Is that true that after adding physical memory to the machine, we don't have to change anything in Informix config files to use this newly added memory ? We added more 1GB in our box and he told me that Informix reconfigures itself automatically. I thought it were strange because if you are running more instances in this machine, how Informix knows the quantity of memory they need separately ? It can affect performance, since the bigger instance may have less memory. Sorry for my english and thanks for your help. Anderson
He's right in theory, but not in practice. Informix will dynamically add memory segments up to and beyond physical memory ( into swap space ). But this is not something you want to happen. It's better to plan for the memory requirements and set the initial shared memory segment that Informix will grab to account for peak usage. Things tend to slow down when the engine is managing multiple memory segments. If you want to take full advantage of that memory you may also want to look at your BUFFERS in the Informix instances. They don't grow dynamically and can have a significant impact if you had scaled them back due to low physical memory beforhand... Greg. On 20 May 2003 06:40:34 -0700, asantos@rioservice.com (Anderson Deluiz) wrote: >Hi all, > >I'm not an Informix DBA but I want to check if what our DBA told me >about configuration on Informix after increasing memory on our AIX >4.3.3 box is true. The version of Informix is 7.31UC4, I think. > >Is that true that after adding physical memory to the machine, we >don't have to change anything in Informix config files to use this >newly added memory ? > >We added more 1GB in our box and he told me that Informix reconfigures >itself automatically. I thought it were strange because if you are >running more instances in this machine, how Informix knows the >quantity of memory they need separately ? It can affect performance, >since the bigger instance may have less memory. > >Sorry for my english and thanks for your help. > >Anderson