This section is devoted to the commands that show memory and CPU consumption. As you know, an Oracle database does not exist in a vacuum. If the database server is experiencing a CPU overload or a memory-swapping problem, no amount of Oracle tuning can relieve that. Hence, it is very important that you be able to see when your server is overloaded.
The commands described in this section often differ between Unix dialects. Some dialects, such as Solaris, do not support memory-display commands. In those cases, GUI tools such as glance must be used to see memory values.
In DEC Unix, you can use the uerf command in conjunction with grep to display memory size. For example:
uerf -r 300 | grep -i mem
Here, the output of the uerf command is piped to grep to filter out and display the segments relating to memory. The -i option causes grep to find both uppercase and lowercase strings. With respect to the example shown here, grep -i mem looks for both MEM and mem.
In HP-UX, you can run the glance or sar utilities in order to see the amount of RAM available. The glance utility displays a screen showing CPU and memory utilization both for the system as a whole and for individual processes. The sar utility displays a complete set of system settings and also shows overall server performance. Because it consists of more than 50 screens, a discussion of sar is beyond the scope of this text. For more information on ...