Informix and multiple instances

Hi, I'm the sysadmin at a HP/Informix site, and we are currently looking at running many instances on the same platform. What I would like to know the advantages/disadvantages of doing this from anyone who has experience with lots of instances. We are looking at 10 medium size instances SIZES (GB): 48 < range > 2 USERS : 130 < range > 20 all in one about 230GB, 700+ users And I would like to get a feel for the impact it will have on the system. I'm thinking that there will be major benefits by decreasing the loading on the systables by dividing them up, also in giving the ability to restore a particular instance to a different point in time (something impossible with a dbspace in a single instance, and very necessary!) -- but it will increase the "load" by increasing the number of processes doing database work (i.e. oninit etc), and the contention for processor time. The OS is HP-UX 11, 64 bit The DB is Informix 7.30 FC 6-1 All thought welcome, thanks in advance, - caf caf0013<XX-REMOVE-XX>@yahoo.com - -----------== Posted via Deja News, The Discussion Network ==---------- http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own

You seem to have thought about and understood the issues well. I try to maintain as many separate instances as I can withput degrading performance. Each instance, even a lightly-used one, has an overhead of memory usage. Say around 100M for a database server with a small (BUFFERS~5000) cache. The reason for this is the maintenance of independence of applications - it's a headache at a stressful time when a server is ill to try to think of all the groups of users you must contact, and they key tasks running, if you want to take down or restore the server. Each additional server increases the need for message queues and semaphores, so the kernel needs some tuning. Neil caf wrote in message <7g4pgo$1n5$1@nnrp1.dejanews.com>... >Hi, > >I'm the sysadmin at a HP/Informix site, and we are currently looking at >running many instances on the same platform. > >What I would like to know the advantages/disadvantages of doing this from >anyone who has experience with lots of instances. > >We are looking at 10 medium size instances > >SIZES (GB): 48 < range > 2 >USERS : 130 < range > 20 >all in one about 230GB, 700+ users > >And I would like to get a feel for the impact it will have on the system. > >I'm thinking that there will be major benefits by decreasing the loading on >the systables by dividing them up, also in giving the ability to restore a >particular instance to a different point in time (something impossible with a >dbspace in a single instance, and very necessary!) -- but it will increase >the "load" by increasing the number of processes doing database work (i.e. >oninit etc), and the contention for processor time. > >The OS is HP-UX 11, 64 bit >The DB is Informix 7.30 FC 6-1 > >All thought welcome, >thanks in advance, > >- >caf >caf0013<XX-REMOVE-XX>@yahoo.com >- > >-----------== Posted via Deja News, The Discussion Network ==---------- >http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own