Many different statistics can be collected and monitored by OverTime.
Types of collections can be categorized by the collection/s that may be in
existence when OverTime is run. The following categories will be explained
below: I/O, User Specified, External Collections and PingTime.
Which SNMP Object IDs are configured by OverTime for collection can be controlled via the templates file. These collections are called "Template Collections " in this documentation. Through Template Collections you can specifiy for each kind of device not only which SNMP OIDs to collect but also how they should be labelled, grouped and the text for the graph title and Y-Axis etc.
To collect interface traffic statistics for Input/Output type devices like routers, switches and hubs, simply select the prediscovered device on the OpenView map and then run the Add/Update menu item (found under Misc, OverTime Actions). OverTime tries to find any existing collections for this device. If there are none or if I/O* collections already exist for this device, OverTime then queries the device looking for I/O interfaces that may be operational to add to the list of collections. The interface must be administratively Up, be reporting a non-zero interface speed that is also less than 400Gb and actually be able to be queried for the SNMP OIDs ifInOctets and ifOutOctets. If the interface provides the SNMP values for ifInErrors and ifOutErrors, then these are also collected. If the device supports CiscoAvgBusy5 MIB OID this is also included in the list of collections.
OverTime creates the collection entries and signals OpenView to add these to the list of collections performed by OpenView’s snmpCollect.
If there were no previous collections and RRD file for the
interface/instance, then the default sample_time value is used for the
frequency of collection and the creation of the RRD. (If sample_time is not
specified in the file overtime.cfg a default of 300 seconds or 5 minutes is
used. See Below.)
OverTime creates all necessary directories for the new device. A directory is created in the web server’s area (under OverTime) to hold the graphic files created.
OverTime creates a directory (under OverTime\data) to hold the RRD files (1 RRD per interface or instance).
OverTime creates a master configuration file for the device. This plain
text file contains the list of interfaces being monitored, one per line. For
I/O collections, each line has four values on it with the first three blanks
separating the 4 values and takes the form:
Interface-Number Code Threshold “Title
Interface-Number is the SNMP Instance Number for this interface;
Code is one of a 0, 1 or 2;
Threshold is a user modifiable threshold that draws a line on the resulting graphs if the values plotted approach the threshold;
“Title is a user modifiable title for the graph;
The threshold and title are initially set from values taken from the device.
The default threshold value is the interface speed for interfaces OR 100% for CPU.
The default titles are the interface names.
OverTime updates/creates the master html page (which by default is index.html) in the web servers OverTime directory. The devices are listed on this page in alphabetical order (case sensitive). The name chosen for the device is either 1) its SNMP sysName or, if that is blank, an IP address from the device with first preference given to any loopback address discovered on the device or 2) the OpenView selection name for the device. This is controlled by the "indexbysysname" (see overtime.cfg later).
When an Add/Update is run, if OverTime finds existing active non-IO* collections for this device in OpenView’s snmpCollect.conf file, then these collections are setup in a similar manner to I/O collections except:
In the master configuration file, a group of lines is added for each
non-IO collection. I.E. if a collection for an OID called DiskSpaceUsed
existed, then a group of lines would be added where the first line indicated
that DiskSpaceUsed was being collected. Each subsequent line in the group would
relate to an instance of this (lets say a disk drive) and the group would be
terminated by a line with nothing on it. When viewed through your browser, this
group would appear on the device’s main page as a single graph, with a line for
each instance (disk drive).
When Add/Update is run, if both I/O and non-IO collections are already active, then OverTime will setup for both types as explained above.
* I/O Collections are collections on ifInOctets, ifOutOctets, ifInErrors, ifOutErrors, sysUptime and CiscoAvgBusy5.
* non-I/O collections other than those listed as I/O. This includes expressions.
OverTime can be used to store and display non-SNMP information via external collections.
OverTime can display ping response times from a Cisco router to any IP address. PingTime collections are performed by the PingTime application.