Steve (and others),
I have experienced the same problems you describe when our network
technicians perform maintenance on our routers. Vast quantities of
historical data become orphaned in an instant. I have > 35,000 objects
in my database, so recovery after even one such change can be long and
arduous.
To help alert me to changes, I've written some programs that use
snmpwalk to periodically get the interface information for the routers
from which we are collecting data. When a MIB instance/interface
description changes, I get mail. I keep a number of unique copies of the
output to help audit changes.
Currently, we're still on V4.1 and use the flat file method of storing
data. This storage methodology doesn't lend itself to tracking changes
easily, which means that I have to migrate the data to be recovered by
snmpColDump-ing data from one file and adding it to a new or different
one when interface MIB instances change.
The scripts supplied with Netview to move the data to an external
database don't ease the problem much because the database structure
itself is pretty flat. I'm considering creating my own scripts that feed
the data into tables where the association of site to interface and
interface to MIB instance is also kept in the database and is interval
encoded - i.e. the associations are stored with dates that give the
"life" of the association. If anyone has attempted such a structure, I
(we) would love to hear it, particularly to hear of any inherent logic
holes.
This approach seems too complicated to me to solve a problem I would
rather solve at the router level.
-John Grover
Steve Cochran wrote:
>
> For long-term statistics we use the freeware tool MRTG
> (http://ee-staff.ethz.ch/~oetiker/webtools/mrtg/mrtg.html) but we have
> outgrown it and are currently looking for a good commercial solution.
>
> On the subject of utilization reporting, I'm curious what others do
> when you install or remove hardware interfaces from routers. In the
> case of Cisco, and I believe most other devices, SNMP instance numbers
> are assigned to each interface at boot time. If you add or remove an
> interface and reboot the router, the router may number interfaces
> differently. (For instance if you have a router with a serial port,
> a HSSI port, and an Ethernet port they might be numbered 1, 2, and 3.
> If you remove the hssi port and restart the router the serial port
> will still be instance 1 but the Ethernet port will now be instance 2.
> Now the HSSI and Ethernet statistics are mingled and separating them
> becomes a major hassle.)
>
> I would think this would be a common problem in any network that is very
> dynamic, but I am not aware of any tool that can handle this intelligently
> (by storing its data according to the interface description instead of
> the SNMP instance, for instance). Does anyone else have this problem?
>
> Thanks,
>
> Steve Cochran
--
---------------------------------+--------------------------------------
John Grover | Operations Manager,
UNET, Technology Services | Senior Technical Support Specialist
University of Maine System | JGrover@Maine.edu
Computing Center | phone: (207) 581-3510
Orono, ME 04469 | fax: (207) 581-3531
|