Linux server performance monitoring
Along with website and services availability monitoring we provide Linux server performance monitoring. It includes:
- CPU usage monitoring
- memory monitoring (incl. swap usage)
- disk space usage monitoring
- bandwidth monitoring
- and load average monitoring.
Below short overview of each item is provided.
CPU
![server CPU statistics chart](http://www.serverbeep.com/images/cpu.jpg)
user: part of time CPU executes at the user level (application).
nice: part of time spent by CPU while executing at the user level with modified priority.
system: part of time spent by CPU at the kernel level.
iowait: part of time that the CPU was idle during which the system had an outstanding disk I/O request.
idle: part of time that the CPU was idle and the system did not have an outstanding disk I/O request.
One of the most important parameters is iowait. Unless it’s less than 20-30 your server performs well.
Memory
RAM
![server swap statistics chart](http://www.serverbeep.com/images/memory.jpg)
used: amount of occupied memory.
cached: disk caching. Used to make the system faster, actually it’s available for the application memory.
free: value of free memory.
If it appears confusing you could check nice explanation of Linux memory here.
Swap
![server memory statistics chart](http://www.serverbeep.com/images/swap.jpg)
Usually Linux uses swap memory only if there’s no free RAM memory. If your system’s swap usage is about 0 it means that there’s no lack of RAM memory problems. But if system uses swap a lot it could mean you might want to consider adding more memory or to optimize the applications.
Disk space usage
![server disk usage statistics chart](http://www.serverbeep.com/images/disk_usage.jpg)
With serverbeep’s daemon you can choose what partitions space usage you want monitor.
Bandwidth
![server bandwidth statistics chart](http://www.serverbeep.com/images/network.jpg)
Bandwidth monitoring is also one of our service features and probably one of the most critical for server monitoring.
Load average
![server load average statistics chart](http://www.serverbeep.com/images/server_load_chart.jpg)
The simplest definition:
In short it is the average sum of the number of processes waiting in the run-queue plus the number currently executing over 1, 5, and 15 minute time periods.
High load average is one the most common issues on Linux server. There could be a lot of sources but the most frequent are: Apache, MySQL and the applications code. Say, if your server LA is less than 10 you are safe.