Re: BUFFERS! Arghhh!!! Please help before I do something silly!

back in the buffers, If your are going to increase buffers I would recommedn increasing LRUS to 256 or 512. esteban.- "Andrew Hamm" <ahamm@mail.com> wrote in message news:<c6n0uj$dlr36$1@ID-79573.news.uni-berlin.de>... > sumGirl wrote: > > I am confused. I posted last week with questions about how I should > > tweak my onconfig after I added memory to my RS6000 (from 4 gig to 8 > > gig). One of the comments that really stuck with me and in the > > responses many folks agreed with was that I should "up my BUFFERS" but > > today I did a search on recent posts within this discussion group and > > found lots of folks warning against raising buffers...thus the > > ARRGGGHHHH! > > > > I was all set to "up my BUFFERS" tomorrow evening during some > > scheduled maintenance, but now I am stressing out about it. Currently > > they are set to 150000 and I thought I would up them to 250000. My > > LRUS are 64 with MAX=2 and MIN=1. CLEANERS is 64. My onstat -p shows: > > Have you addressed all the other points yet? Do you wish to deal with them > one by one? If you are after reliable improvements in a hurry, you'll have > to spend more time online discussing all the suggestions. > > I've reviewed the suggestions, and I think if you are NOT using KAIO then > the setting NUMAIOVPS=2 is going to be the most crippling. What is the > output of > > onstat -g iov?> > As to the increase in buffers... The counter-argument to adding hundreds of > thousands of buffers is that more dirty pages can be stacked up, so your > checkpoints can be longer. > > Art, how does the BTR formula and recommendations go? > > Anyway, list all the suggestions in point form, then either understand them > and plan your action, or ask further questions until you know what each idea > means and what the ramifications are.

On Thu, 29 Apr 2004 09:02:51 -0400, sumGirl wrote: > Thanks for the info all...I made the change and no fires this morning. I did > however notice that my checkpoints increased from around 4 seconds to 10 > seconds. I know Art specifically mentioned that this might happen, amongst > other folks, so I was wondering what I should tweak first - LRU*s or > CLEANERS? > > When I raised my buffers, I set LRUs and CLEANERS both to 84. The MAX and > MIN are set at > LRU_MAX_DIRTY 2.000000 > LRU_MIN_DIRTY 1.000000 CLEANERS and LRUS seem to be sufficient without more info. How many chunks do you have? Set CLEANERS to at least 1.5*#chunks plus a few, if the 84 is more than that then leave it. Looks like you're running 9.4, try reducing LRU_MAX/MIN_DIRTY to 1.0 and 0.5 or 1.0 & 0 that alone should cut checkpoint time in half. Art S. Kagel

Thanks for the info all...I made the change and no fires this morning. I did however notice that my checkpoints increased from around 4 seconds to 10 seconds. I know Art specifically mentioned that this might happen, amongst other folks, so I was wondering what I should tweak first - LRU*s or CLEANERS? When I raised my buffers, I set LRUs and CLEANERS both to 84. The MAX and MIN are set at LRU_MAX_DIRTY 2.000000 LRU_MIN_DIRTY 1.000000 Thanks for all the good info!