Engine Hang

We have recently upgraded to IDS 7.30 UC7 and Solaris 7 and are now experiencing problems. After running for 1 or 2 hours our engine will hang, running the pstack utility on the pid of the oninits shows a kaio process on the top of the stack. After pstack has been run on the oninit with the stuck kaio process, normal operation begins again (perhaps because pstack stops and restarts the process, I don't know). I called Informix, they -no suprise here- said it was a Sun problem. We are working with Sun, but I was hoping someone else had seen this behavior before. I am unsure of the correct combination of onstat's and unix reports needed to help solve the problem, any help would be greatly appreciated. TIA Robert Douglas