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Troubleshooting High CPU Load

First, open a shell from SSH or the serial/VGA console (option 8).

Typically one of these commands will include some obvious consumer of large amounts of system resources. For example, if the system CPU usage is high, it may be the packet filter. If a VPN process is using lots of CPU, the hardware may not be able to process more VPN traffic. If it is a NIC, see Tuning and Troubleshooting Network Cards, etc.

If the solution is not obvious based on the output, post the collected information on the forum or contact support for further assistance.

View CPU Processes

To view the top processes, including interrupt processing CPU usage and system CPU:

top -aSH

View Interrupt Counters

To view the interrupt counters and other system usage:

systat -vmstat 1

View mbuf Usage

To view the mbuf usage:

netstat -m

Note

Alternately, check the dashboard mbuf counter, and the graph under Status > Monitoring on the System tab.

View I/O Operations

To view I/O operations:

systat -iostat 1

Or:

top -aSH

Then press m to switch to I/O mode to view disk activity.