RE: Long checkpoints causing crashes

>===== Original Message From William Rice <ricew@operamail.com> ===== >>===== Original Message From Dominic Penfold <bigbaddom_the_first@yahoo.com> >===== >>Hi There >> >>Running IDS 7.30.UC7 on HP-UX 10.20, and the server is >>now hanging most evenings. This seems to be due to >>long checkpoints, you often see one checkpoint of 80 >>seconds or so, immediatley followed by a 2nd >>checkpoint of 0-11 seconds or more, followed by >>Informix Dynamic Server Stopped. > >What is your check point interval? > >>I've heard an idea to reduce the number of buffers, >>saying this will lower checkpoint times and reduce the >>problem. This is from the same person who had BUFFERS >>set to 30000 when I first arrived, with tons of >>ovbufs, bufwaits, and pathetic read and write caching, >>I have now set BUFFERS to 180000 on this 3 gig phys >>memory system, still below the 20-25% recomended. Note >>any advice for BUFFERS setting on a machine that >>shares informix with another application? onstat -p >>shows much better performance now, but could it >>actually be a good idea to cripple the system with a >>crap number of BUFFERS, just to avoid stopping the >>system with long checkpoints? > >The only reason lowering the number of buffers helps is >that means the number of buffers you flush at the checkpoint is >less (1 percent of 30,000 is less than 1 percent of 180,000) >so by multiplying the number of buffers by 6 it is possible your >checkpoints will be 5 or 6 times longer. > >> >>Final note: I thought a core and shm dump may be a >>good idea for tech support to analyse exactly why >>informix is stopping, but I don't see how this is >>possible, as it is not an assertion failure. > >Informix is most likely pausing for normal reasons. Oops, I missed the part about Informix Stopped, If we could see the message file that contains this that might help >Could you post onstat -p, onstat -c, onstat -m, onstat -d > > >Will ------------------------------------------------------------ This e-mail has been sent to you courtesy of OperaMail, as a free service from Opera Software, makers of the award-winning Web Browser, Opera. Visit us at http://www.opera.com/ or our portal at: http://www.myopera.com/ Your free e-mail account is waiting at: http://www.operamail.com/ ------------------------------------------------------------