Part 3: System Reporting
Know what you're monitoring for...
You cannot have low latency and high throughput. They mutually exclude one another. Database server should be low latency whereas file servers would have high throughput.
Main areas to focus on
- Memory - Very important to overall performance
- Disk - Very important to overall performance
- Network - Not always important
- CPU - Not always important, but has many tuning options.
Common tools to use
Use the man pages to view all of the options and switches for each tool.
- sar - system activity reporter
Make SAR sortable. Add
alias sar='LANG=C sar'to /etc/bashrc
The gathering cron is /etc/cron.d/sysstat
The first entry is the frequency sa1 will run (Default 10 minutes)
The second entry is the sa2 frequency. (Default is once a day at 23:53)
- top - generic overview of the system
To create a new default view:
Fuse the arrow keys to choose a field to add then press
Confirm the new view and type
Wto save the default view you the user's home.
- iostat and iotop - information about I/O
iotop is not a default package. install it with
yum install -y iotop
- vmstat - virtual memeory stats