1 Linux Monitor command: top, sar, iostat, /proc/meminfo …

Monitor overall system

top

-p		Show particular PID
-d		refresh secs
1		show individual CPU information
sorting	P	Sort by CPU usage
	M	sort by memory usage
	N	sort by PID

vmstat

vmstat report memory and CPU information.  In the below example, it means collect information every 2 secs for 3 times.

vmstat 2 3

sar

sar also can report the CPU, memory and disk IO information base on the parameter.

sar 2 3

This example means collect the information every 2 secs for 3 times.

sar –r 2 3 

-r provide more detail of the memory

sar –b 2 3

-b provide the disk IO information.

Monitor CPU

uptime: This provide the idea for general host level loading. Large number means higher load.

Monitor Disk

collect information every 2 secs for 2 times.

iostat 2 2

Monitor memory

mpstat

mpstat 2 3

collect information every 2 secs for 3 times.

free

General memory utilization on the host.

/proc/meminfo

Snapshot for the host memory usage.

cat /proc/meminfo

ipcs

show shared memory in the Oracle SGA.

Others

ipcrm: Remove the message queue or shared memory.