We help IT Professionals succeed at work.

We've partnered with Certified Experts, Carl Webster and Richard Faulkner, to bring you a podcast all about Citrix Workspace, moving to the cloud, and analytics & intelligence. Episode 2 coming soon!Listen Now

x

Performance impact of enabling "Logging buffered 5" on a Cisco 26xx router

Medium Priority
370 Views
Last Modified: 2013-12-24
Hi,

I have a Cisco 26xx router (2 WAN ports & one LAN port).

Currently logging is not enabled, so when doing "show log" nothing was shown.
There's been cases of the router flipping (think HSRP flipping) but we don't know
if it's the Telco's leased line that caused it or the router itself, thus my idea of
enabling logging.

I intend to do the following :
> show memory exec      (to get free memory)
> logging buffered Half_Free_Available Memory 5
         (level 5 messages & below, leaving out informational ones).

We have 2 x 2Mbps links connected between local site & remote site.


Pls give your thoughts whether the performance of the 2 pairs (1 pair at our end
& 2 more pairs at the other end) of Cisco routers would be affected as I'm setting
logs to use half of the available memory.

Not in time to set the logging to log to a syslog server but would doing so (to a
remote syslog) help?

Kindly give ideas what's the optimal value to set for the logging (amt of memory)
as well as the message levels (0-7 : just want to log cases of interfaces timed
out or flipping or router itself causing a HSRP switch).  What to check for CPU
(sh proc cpu?)

Basically we don't want performance to users to be affected due to logging
being enabled on routers
Comment
Watch Question

Commented:
Why are you using logging buffers so large?

I normally use 8K to  100K  buffers.
The performance impact (if any)  should be minimal.

I actually recommend logging to a remote server using syslog (setup a Linux or UNIX server to accept the log entries over remote syslog),  and keeping 8K of buffer on the local device.

This way you can get at a most-recent history by logging in, while having the past week of logs on a Linux server.

Not the solution you were looking for? Getting a personalized solution is easy.

Ask the Experts
Commented:
That is: the performance of enabling logging on a router is normally negligible.

It can potentially be greater if you pump up the logging level and start enabling debugs,  but logging alone is nil,  and it's a very bad configuration to not have any logging enabled.

Author

Commented:

When I issued "show log" on the pair of Cisco 26xx, it just showed "logging on" and
a few lines indicating the logging is enabled.  Why is that there's no logs (was expecting
to see messages like "adjacency down", "line protocol up/down" kind of messages.

What's the command for me to find out the existing logging settings (buffer size, message
levels etc)
Access more of Experts Exchange with a free account
Thanks for using Experts Exchange.

Create a free account to continue.

Limited access with a free account allows you to:

  • View three pieces of content (articles, solutions, posts, and videos)
  • Ask the experts questions (counted toward content limit)
  • Customize your dashboard and profile

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

OR

Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.