Re: Please help on BUFFERS configuration

Fernando Collalti wrote: > Question: > The actual BUFFERS=20000, the physical memory is 256MB RAM, I would like to > increase > the BUFFERS to 40000, because I have to many buffers waits and the "Read % > cached" is to > low (86.16). > When I change the BUFFERS parameter from 20000 to 40000, in order to take > effect, I need > to bring down the engine (initialize), will my data be safe? Is changing > this critical parameter > safe? > CLEANERS 14 # Number of buffer cleaner processes > LRUS 14 # Number of LRU queues Yes this is perfectly safe. Just bring the engine off line (onmode -sy and wait for all processes to detach or onmode -ky and force everyone off). Then modify the ONCONFIG file and run oninit (WITHOUT THE '-i' parameter which would INITIALIZE the root dbspace and wipe out your databases) to bring the engine back online. BTW, while increasing BUFFERS will help your READ CACHE % the bufwaits is more dependent on the number of LRU queues. There is also a bug, or at the very least a suspected bug, that causes very high bufwaits at certain numbers of LRU. Until now the only known such values are 64 and 96, perhaps 14 is another node in this function?! Try increasing LRUS and CLEANERS to 32, this is a known good value and should be better for 40000 BUFFERS in any event. Please let me know what happens as I am tracking this bufwaits problem. Art S. Kagel