Re: Re[2]: Long checkpoints (LRU_xxx_DIRTY/LRUS)--NETTYPE values

> Our physical log is 250 MB, which is quite big (but I want to avoid > physical log overflows by all means). The value for LOGBUFF is 128. Hm. I've never heard of a _physical_ log overflow. I take it then that you never have the physical log kick off a checkpoint? Perhaps you can shrink that a bit. Or a lot. :-) > PHYSBUFF is 4096. We are using SAP, so we must use unbuffered logging. Also a bit high in most sites, but (probably) fair enough for SAP. > The disk containing rootdbs and physdbs contains nothing else. The Can you move the physdbs to a separate spindle? > disks containing our logical log files also contain nothing else. > > Yesterday, I had to extent a couple of dbspaces, which apparently > forces a checkpoint. So this forced several checkpoints within a > couple of minutes. Each of these took more than 15 seconds ! At one > of these long checkpoints, there were even less than 1000 dirty pages. > > I don't know if my NETTYPE values can cause problems. I use CPUVPS > for both protocols (SHM and TLI). I use 1 poll thread for the shared > memory connections and 5 poll threads for the used TLI connections. > I know that the manuals say that only one protocol can run his poll > threads on CPU vps, but there are no error messages in the message log > at startup of the Informix instance and also the onstat -g ath output > indicates that poll threads of both protocols are running on CPU VPs. Interesting. >My ONCONFIG file : >------------------ >AFF_NPROCS 0 >AFF_SPROC 0 Processor affinity not supported? This might help overall performance if it is. >CKPTINTVL 1200 What happens if you drop this to 300? Do you still get such long checkpoints? >RA_PAGES 32 >RA_THRESHOLD 24 Hm. Does SAP do a lot of sequential scanning then? >ROOTPATH /informix/PR1/sapdata/physdev1/data11 Stupid question I know, but is this a raw device? >SHMVIRTSIZE 1310720 Isn't this a bit big? Good luck! -- "I'll Be Back" Obnoxio ************************************************ Sane? Hell, if I was sane, why would I be here? Get Your Private, Free Email at http://www.hotmail.com