RE: Long checkpoints causing crashes

>===== 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. 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/ ------------------------------------------------------------