Devices Page

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Name

Devices -- A container for a collection of sub-devices

Description

List

List of devices in a group; this is the default view when you click on a group name.

Name: click on the name of the device to view the sub devices contained in it

SNMP Options

View Interface Cache (): views a list of cached interfaces (interfaces and values that NetMRG knows about)
Recache Interfaces (): recache the interface list (to get new ifAliases or new interfaces, for example)
View Disk Cache (): views a list of cached disks (disks and their values that NetMRG knows about)
Recache Disks (): recache the list of disks (to get new disks or paths, for example)
Recache Properties (): recache the properties of the device (serial numbers, software versions, etc)

Add: add a new device or an existing device to this group
View: views graphs assocated with this device and allows you to edit what graphs are associated with the device
Edit: edits parameters of a device
Delete: deletes the device all sub-devices, monitors, etc underneath it

Add

Create a new device: creates a new device in the current group
Add an existing device to this group: puts a link to an existing device in this group (does not copy it, just refers to it; they are the same device
Device: Name of the device to add to this group

Edit

Edit info about a device

General

Name: Name of a device; commonly the hostname
IP or Hostname: IP address of the device, or hostname (must be resolvable by the monitoring box)
Device Type: Type of device (currently not used)
Disabled: Don't gather data for this device

SNMP

SNMP Support: The version of SNMP to use when querying this device, if any.
SNMP Read Community: The SNMP community string to use when querying this device.

Recaching Method

Methods used by the gatherer for determining if its SNMP cache is stale.

Never refresh cache: The gatherer will never automatically refresh the cache. The cache must be refreshed manually when changes occur.
Refresh on SNMP agent restart: The gatherer will refresh the cache if the SNMP agent uptime goes backwards, or if the device has become reachable again after a period of unreachability. This option is useful for devices that change interface counts too often, such as a router serving DSL sessions.
Refresh on interface count change: The gatherer will refresh the cache if the "ifNumber" value has changed since the last gathering. This typically happens when cards are added to or removed from a router, or when PPP sessions go up or down. (Also includes the above.)
Refresh on interface count mismatch: The gatherer will refresh the cache when the number of items in the interface cache do not match the "ifNumber" on a device. This can prevent problems when devices are in the process of booting. This is the preferred option for most devices. (Also includes the above.)
Always refresh cache: Always refresh the cache on each gather. This is useful for devices that are always changing, when you care about the changes.

Advanced SNMP Options

Disable SNMP Uptime Check: Allows NetMRG to work with devices that are broken or abnormal with respect to system.sysUpTime.0. NetMRG usually uses this value to determine if a host is up and if the SNMP agent has restarted since the last polling cycle. It should only be used when absolutely necessary as it reduces the robustness of the SNMP avoidance and recaching mechanisms which can be crutial to performance.
Unknowns on SNMP restart: This option will write unknown values to the RRD files for all non-gauge values for the first polling after a device restarts. This reduces "spikes" on the graphs by informing RRDtool that a discontinuity in the monitoring has occurred. A downside to this is that you miss an interval of data, which is why this feature can be disabled if needed.
SNMP UDP Port: UDP port to direct SNMP queries to (default is 161).
SNMP Timeout (microseconds): Number of microseconds to wait for a response to a query before retrying (default is 1000000 or 1 second). An exponential backoff is used after each failed query; this is the initial delay.
SNMP Retries: Number of times to query the device before giving up (default is 3).

SNMP Cache View

List of cached values for a device

Interface Cache

List of Interfaces NetMRG knows about

Index: SNMP ifIndex
Status: SNMP ifAdminStatus/ifOperStatus
Name: SNMP ifName
Description: SNMP ifDescr
Alias: SNMP ifAlias (commonly the 'description' field on routers and switches)
IP Address: IP address of this interface
MAC Address: MAC address of this interface
View: View the graph for this interface (if monitored)
Monitors: View the monitors for this interface (if monitored)
Monitor/Graph: Choose to graph this interface (adds an interface subdevice based on ifDescr, adds monitors for ifInOctets, ifOutOctets, and ifInErrors for the subdevice, and assocates a graph with the device)

Disk Cache

List of Disks NetMRG knows about

Index: SNMP dskIndex
Device: SNMP dskDevice
Path: SNMP dskPath
View: View the graph for this disk (if monitored)
Monitors: View the monitors for this disk (if monitored)
Monitor/Graph: Choose to graph this disk (adds a disk subdevice based on dskPath, adds monitors for KB Used and KB Available for the subdevice, and assocates a graph with the device)