The operating system keeps track of how many pages are scanned each second. When memory requests are light, the scan rate will be near zero. When memory is aggressively being requested, the scan rate will be greater than zero. On Solaris, administrators like to see the scan rate near zero. On SunOS and HP-UX, the key number is 200. For example, on HP-UX, if the scan rate is frequently exceeding 200, this means there is truly a lot of memory pressure. Said another way, Oracle memory requirements have exceeded the operating system's memory capacity.

When available, the scan rate can be seen in vmstat reports, in the sr column. When running sar, the command-line option is -g.

I have learned over the years that memory issues are one of the most sensitive issues for administrators and especially with vendors. When you see a memory bottleneck, think there may be one, or you're just not sure, simply ask the operating system administrator. If you run the commands I presented, give the situation some thought, and then approach the operating system administrator, he should respect your honest and concerned request.