Pertaining to the recent discussion of buffpool sizing (larger vs smaller - cpu usage, etc) I would like to get some opinions.
I followed the discussion and was aware of the issue of going too large and killing any benefits by increased CPU usage and such. So, I have been experimenting. My big Linux TSM server has 8GB RAM and is dedicated to TSM, so other products using/sharing the memory is not an issue. The TSM DB is 160GB assigned with 77% used. The buffpoolsize (with selftune) was set to 768MB. I just bumped it to 1GB (still at the 1/8 of real memory guideline) to see if it would improve things, using EXPIRE INVENTORY as a benchmark and trying to ignore the "Cache hit%" value (which I could never keep at or above 99%). Before the change, I was seeing EXPIRE INVENTORY running 46-51 hours. This past weekend, it ran 40H. I realize that having only 1-test result after the change is hardly a good indicator of either positive or negative results. So, my question is this. Do I bump it to 1.25-1.5GB (still well below the "guidelines" of 1/8-1/2 of real memory) and see if that improves things even more or do I drop down to 512MB to see if it improves things even more than the memory increase? Anyone else willing to share their DB sizes/buffpool/expire inventory durations? Open to all thoughts (besides the need for another TSM server......this is already in the works and we have stopped adding new nodes to this server).
