The purpose of this document is to provide a few OS commands for UNIX
operating systems to gather information about Physical Memory (RAM),
swap memory,CPU usage and idle percentage, whether lots of processes
are in the process run queue and whether too much paging and swapping
going on in the server or not so that we can use the information along
（本文来源于图老师网站，更多请访问http://m.tulaoshi.com）with Statspack report to help diagnose the Database Performance issues.
Sometimes, the information gathered using these commands will be helpful
in finding the most OS resource consuming database or non-database
processes and will help in identifying the processes to further
investigations about why the processes are consuming so much resources and
whether the corresponding query or application needs to be tuned.
SCOPE & APPLICATION
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This document can be used by anyone with moderate expertise to run UNIX
OS commands in various operating systems like Solaris, HP-UX, AIX, TRU64,
Linux, etc. The commands will help us collect OS related information
to verify whether overuse of any of the OS resources can be affecting
the database performance or not. This document does not deal with OS
Kernel tuning.
How to use OS commands to diagnose Database Performance issues?
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You want to gather data for Physical memory, Swap space, CPU % usage
and idle, IO usage in the server in general and also to find a few most
OS resouce consuming processes to get better understanding about
how the UNIX server is performing and whether any of these resources
are causing a bottleck in the database performance or not.
Since the popular UNIX systems do not support the same commands or even
same options for a command, we are proving different commands for different
OS in the following section. Please refer to the corresponding OS man pages
for detailed information about each UNIX command mentioned in this document.
Solaris:
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$ /usr/sbin/prtconf |grep -i "Memory size"
$ swap -s
$ df -k
$ /usr/local/bin/top
$ vmstat 5 100
$ sar -u 2 100
$ iostat -D 2 100
$ mpstat 5 100
Out of these commands, top command may not be installed in your server by default.
In that case,you can get it for free from www.sunfreeware.com and install it preferably
under /usr/local/bin directory and then use it. Please take a few snpshots of the
top command output and store it in a file.It refreshes the output screen every 5 sec.
（本文来源于图老师网站，更多请访问http://m.tulaoshi.com）Prtconf command will show how much Physical Memory (RAM) the Solaris server has.
Swap command will provide us with the usage of swap space including the RAM.
Df command will indicate how much space is free in each mount point and also
provides information about swap space(s).
Top command wil provide the above information plus information about top CPU
consuming processes, CPU usage in the system, etc.
Vmstat will provide information about process run queue, memory usage,
paging and swapping and CPU % usage in the server. Different options in vmstat
can provide more specific information, if req
