[mrtg] Re: Okay to remove mrtg.ok?

[Daniel R . Kilbourne]

it is not ok to remove it. in many cases it will not break anything, but if the reboot of the device is due to an IOS upgrade, or adding an interface then the ifIndexes will change. Basically, o be sure that everything is OK, you should re-run cfgmaker and compare the results to your old config (although I have only had to do this on our 72XX and higher Ciscos).

Also, Cisco has FINALLY addressed the issue of ifIndex's changing when rebooting:


and I quote:


In previous implementation of the IF-MIB there was no guarantee that
the ifIndex value for any "interface" would remain the same after a
system reboot. This caused problems for other MIBs/applications that
used the ifIndex to identify an interface of interest, for example
if an RMON alarm is configured to monitor a variable tied to an
interface (say ifEntry.20.1).
 Expressions in the Expression MIB are not persisted
across reboots because there is no guarantee that ifIndices are
persisted.

Feature Description
-------------------

The ifIndex Persistance feature allows for such persistence for
interfaces and dependent expressions. The ifIndices is persisted in
non-volatile storage(NVRAM/Flash) which is available and readable
at registration time.


CLI commands to enable/disable ifIndex persistence
--------------------------------------------------

A per interface setting will override the global setting. The default
setting will be the same as the global setting.

Persistence can be enabled by saying:
   snmp ifindex persist
and disabled by saying:
   no snmp ifindex persist

(eg)The following config command sequence will enable persistence for
interface "ethernet 0/1" alone:

  interface ethernet 0/1
  snmp ifindex persist

The interface specific setting can be cleared by saying:
  snmp ifindex clear

After this config command is executed, the interface will revert to
following the global persistence setting.

(eg)The following config command sequence will clear the persistence
setting for interface "ethernet 0/1" alone:

interface ethernet 0/1
snmp ifindex clear



Peter Lalor wrote:
> Hi all,
> 
> I have frequent problems with interfaces moving around, which 
> prevents MRTG from updating the affected graph until mrtg.ok is 
> edited or removed. I'm wondering if it's okay to have cron remove 
> mrtg.ok, say hourly, to prevent any graphs from not being updated for 
> longer than an hour in the even that I don't fix the mapping manually.
> 
> For bonus points, if it's okay to remove mrtg.ok, what's the point of 
> it in the first place? ;-)
> 
> (I understand that RRDtool fixes this problem of graphs breaking when 
> interfaces move. Unfortunately, I can't get RRDtool to make on my 
> system, Mac OS X Server.)
> 
> Thanks.
> -- 
> 
> Peter Lalor           Infoasis
> plalor at infoasis.com   http://www.infoasis.com/
> 
> "Where's my burrito?" -- Homer
> 
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-- 
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Daniel R. Kilbourne
daniel.kilbourne at voyager.net
Voyager.net Network Engineer

^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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