Re: system speed

There are several major aspects in performance tuning: 1) Disk I/O 2) Memory 3) CPU 4) Application/Types of queries/DB design 5) Network ** Listed in the order of "most likely occurence of bottelneck" Performance tuning is an art. You can't learn it right from the book - it takes time. But I'll share with you some key points. Behind these points there are many subtle details waiting for you to find out. Disk I/O -------- Assuming you have high performance disks, the key here is to balance disk I/O across all disks on the system. Memory ------ IDS requires as much memory as possible to perform its best. So make you allocate enough memory to IDS... but also be certain that the OS doesn't run low of memory just because you've allocated too much memory to IDS. Again, balance is the key. The READ CACHE & WRITE CACHE percentage from onstat -p should show at least 97% and 87% respectively. There are also resident and virtual memory to think about. Make sure you allocate enough virtual memory in order to avoid IDS having to allocate additional segment of virtual memory dynamically ~ which slows down performance. And many other factors. CPU --- Make sure you allocate optimum number of CPUvps. Output of onstat -g rea/act should help you to tune this. If the problem is the physical CPU, easy! add more CPU. Application/Types of queries/DB design -------------------------------------- All queries should hit the indexs in the db. If not, either create the necessary indexs or change the query. Many other factors... very technical here as well. Network ------- Tranfer rate over the network. If network transfer is the bottleneck, get the network people to fix it ~ may need upgrade to allow more bandwidth. Special consideration in Client/Server programming techniques exist to optimise the performance of such application. Grab a book and study them. On Wed, 05 Aug 1998 13:23:27 GMT, "Matt Devlin" <mhdevlin@nycap.rr.com> wrote: >I am a junior DBA and have been assigned the task of analyzing our informix >engine and making recomendations on how to improve performance. Obviously >there are far too many variables to post in one posting. Would anyone out >there care to offer some assistance in this matter. I am very new to to >informix and would appreciate any help. The instance is running on a SCO >box with four intel 200 p-pro's. 700 megs of ram, over 100 users on a busy >day. I think at this point there will not be any physical changes made >unless a dramatic improvement could be acheived for minimal expense. We >really want to tune the engine. > >