Troubleshooting High CPU Utilization

Cisco 7500 Series Routers, Troubleshooting TechNotes

* High CPU Utilization in Exec and Virtual Exec Processes

* The show processes Command

* Troubleshooting High CPU Utilization Due to Interrupts

* Troubleshooting High CPU Utilization due to Processes

* Troubleshooting High CPU Utilization in IP Input Process

* Troubleshooting High CPU Utilization on Cisco Routers

* Understanding VIP CPU Running at 99% and Rx-Side Buffering

* What Causes %SYS-3-CPUHOG Messages?

IOS Syslog facilities

Logging and debugging messages are the cornerstone of troubleshooting.

There are 4 possible destinations for Logging:
1.Console
2.Monitor
3.Buffer
4.Host
+plus SNMP

R1(config)#do sh logging
Syslog logging: enabled (9 messages dropped, 1 messages rate-limited, 0 flushes, 0 overruns, xml disabled)
Console logging: level debugging, 33 messages logged, xml disabled
Monitor logging: level debugging, 0 messages logged, xml disabled
Buffer logging: disabled, xml disabled
Logging Exception size (8192 bytes)
Count and timestamp logging messages: disabled
Trap logging: level informational, 38 message lines logged

Descriptions for the fields in the output above.

When troubleshooting in High CPU utilization situations, and you have to use debugging, make sure to disable or "level-limit" the console and monitor logging facilities. Instead use the buffered logging facility to record the debug output and view it with "show logging". This will allow the CPU to process the log messages in a high utilization environment.

To use a syslog server and set the log-level:

R1(config)# logging host
R1(config)# logging trap ?
<0-7> Logging severity level
alerts Immediate action needed (severity=1)
critical Critical conditions (severity=2)
debugging Debugging messages (severity=7)
emergencies System is unusable (severity=0)
errors Error conditions (severity=3)
informational Informational messages (severity=6)
notifications Normal but significant conditions (severity=5)
warnings Warning conditions (severity=4)

Reference:
Troubleshooting and Fault Management Commands @ Cisco
Troubleshooting High CPU Utilization on Cisco Routers @ Cisco

Portable Product Sheets @ Cisco

Here's a page I came across on the Cisco Site.
Provides easy access to reference documents useful to partners.
Eg: Switch Performance, IOS Packaging, Router Memory/Performance, ISR Ref.Sheets, etc.

Portable Product Sheets

Password recovery references for almost all Cisco Devices

Here's a great reference page from Cisco, explaining the pwd recovery procedures for many of their devices.

Password Recovery Procedures

Internet Map of Autonomous Systems in Türkiye

Here's a recent and very well done study of the Networks/ASs located in Türkiye, by Hakan Çetin.

Türkiye'nin Otonom Sistem Seviyesinde İnternet Haritasının Çıkarımı (TİH) - 2009

Steps for migrating from PIX to ASA

You should be running v7.x on your PIX so that your configuration can be converted properly. Two ways of going about this:

* Tool-Assisted Conversion (Link)
* Manual Conversion

I'll covert the manual method here.
Upgrading your PIX to v7.x

1. Get copies of your config and version/license info

# show running
# write net
# show version

2a. If BIOS is earlier than 4.2, use Monitor Mode instead of copy tftp flash

Reboot and press BREAK or ESC during boot to enter Monitor Mode

monitor>interface
monitor>address
monitor>server
monitor>gateway
monitor>ping
monitor>file
monitor>tftp

PIX will automatically boot, but the software upgrade is only done in Memory, you MUST you go through the steps below to complete the upgrade!

2b. Upgrade System software

#enable
#copy tftp: flash:
Address or name of remote host []? 10.1.6.44
Source filename []? pix701.bin
Destination filename [pix701.bin]?

3. Now you have upgraded your software and your config was auto converted to v7.x
You should go through and check the changes made, which could be very different from your older pix config.

4. Use this config in your ASA appliance. Do this either with the Copy/Paste method, or via a tftp/ftp config file transfer.



Ref: Migration from PIX 500 Series Security Appliances to ASA 5500 Series Adaptive Security Appliances