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High CPU load on 2621 when moving multiple large files

p-allen
Level 1
Level 1

We are seeing the copy load increase to 90% or higher when copying multiple large files accross our WAN link that has a 2621 router on a 100MB link back to our main office. Sometimes we see high ping times and others we lose pings and eigrp loses its neighbor info. What could be the cause? Do we need a beefer router there?

show proc cpu

CPU utilization for five seconds: 97%/93%; one minute: 13%; five minutes: 9%

12 Replies 12

Edison Ortiz
Hall of Fame
Hall of Fame

High ping times and eigrp losing its neighborship means that you are saturating the WAN link. How big is your pipe ?

You may be looking into implementing QoS if that situation is happening often.

You also mentioned the CPU load, can you post your router config? High packet loss can affect the CPU performance.

HTH,

__

Edison.

we have a 100MB link and only see bandwidth increase to 50MB.

show proc cpu

CPU utilization for five seconds: 97%/93%; one minute: 13%; five minutes: 9%

Here is a copy of the config and the show proc cpu

Your ip flow-cache timeout active is quite low. Set to 1 minute currently and this process may be CPU intensive. The default is 30 minutes, try changing to 15 minutes and see if your CPU behaves better.

HTH,

__

Edison.

I changed it to : ip flow-cache timeout active 30 and still had the high cpu load issue occur

Your config seems fine other than that, I recommend looking into a 3800 Series instead of the 2800 Series.

You will get better performance on a 3800 Series while connected to a 100Mbps circuit.

According to this link it appears we should have a least a 2811 router at this location. Does this seem correct to you?

http://www.cisco.com/web/partners/downloads/765/tools/quickreference/routerperformance.pdf

The ISR will definitely process data faster but let's try my recommendation on the previous post before ordering a new hardware :)

I changed it to : ip flow-cache timeout active 30 and still had the high cpu load issue occur

Cisco 2621 can not handle more than 32Mbps

file transfer. I'll give you an example:

I have a cisco 2621 connect to a Catalyst 2960.

The speed and duplex on both the Cisco 2621

and Catalyst 2960 is set to 100 full-duplex.

I have two linux servers on both sides of the

Cisco 2621, also connected to the same Catalyst

2960, interface and speed duplex on the linux

servers is also set to 100 full duplex.

When I performed either a SecureFTP or FTP

servers, the most I would get is 32Mbps

and that the router cpu is at 99% utilization.

I also tested using Iperf using large files

and the CPU is at 99% at 32Mbps file transfer

rate. I am running IOS version 12.3(24)a.

In other words, you will not get 100mbps from

Cisco 2621. It just can not be done.

CCIE Security

Joseph W. Doherty
Hall of Fame
Hall of Fame

I agree with cisco24x7, the smaller WAN routers, such as your 2621, are not capable of continuous 100 Mbps throughput.

If your 100 Mbps WAN link is Ethernet, besides considering faster WAN routers, you might also look at L3 switches. The Cisco Catalyst 3560-8PC might be a good fit.

Once i noticed that whenever i added DHCP server to my network the cpu load would get increased ! Strange!

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