Saturday, March 15, 2014


Load - 1

10:24  up 6 days, 14:52, 4 users, load averages: 1.74 2.07 2.09
1-5-15 minute load average
System load: avg no. of processes in a runnable or uninterruptible state.
Runnable: Waiting for CPU
Uninterruptible: waiting for I/O

1 CPU with  1 Load means : full utilization/ full load
1 CPU with  load 2 : Twice the load that system  can handle

Check what kind of load system is under:

As system that is out of memory can be due to I/O load because the system starts swapping and start using the swap space


Helpful in identifying what resource you are running out of system resources, once zeroed down to that then you can try to find out which what process are consuming those  resources.

top - 13:35:06 up 227 days, 19:01,  1 user,  load average: 0.00, 0.01, 0.05
Tasks: 124 total,   1 running, 123 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   8167620k total,  5987132k used,  2180488k free,   187984k buffers
Swap:   498684k total,        8k used,   498676k free,  5428964k cached

    1 root      20   0 24332 1956 1036 S    0  0.0   0:08.08 init
    2 root      20   0     0    0    0 S    0  0.0   0:00.42 kthreadd
    3 root      20   0     0    0    0 S    0  0.0  16:48.59 ksoftirqd/0
    6 root      RT   0     0    0    0 S    0  0.0   0:33.68 migration/0
    7 root      RT   0     0    0    0 S    0  0.0   0:47.78 watchdog/0

PID: Process ID- unique number assigned to every process on a system

top -b -n 1 | tee output

 wa: I/O wait
This number represents the percentage of CPU time that is spent waiting for I/O. It is a particularly valuable metric when you are tracking down the cause of a sluggish system, because if this value is low, you can pretty safely rule out disk or network I/O as the cause

id: CPU idle time 
This is one of the metrics that you want to be high. It represents the percentage of CPU time that is spent idle. If you have a sluggish system but this number is high, you know the cause isn’t high CPU load.
 st: steal time
If you are running virtual machines, this metric will tell you the percentage of CPU time that was stolen from you for other tasks.

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