I don't use AIX and I do not understand the commands you used except for vmstat. But I can make a few general comments. It is not clear from your post what effect you would like to have on your system. Running out of swap would be a disaster. You would get messages like "can't fork", "out of memory", etc. Many programs do not handle errors like these very well. The box well might crash or lock up and a reboot would be needed to get things going again. Running out of swap means that you are out of virtual memory. Running out of physical memory is not good but perhaps not a disaster. If vmstat showed you a scan rate of 3000+, you clearly had been out of physical memory for some time. Generally, the box can run in this state, but with a performance impact. If you want to check your swap to ensure that were not close to a disasterous out-of-swap condition, that is a great idea, and I hope some AIX expert comes along who knows those other commands you used. But if you want to address that performance problem, you will need more memory. You may be able to make a modest impact on the severity of the performance problem by distributing your swap across more disks. But adding more memory can make the performance problem go away.