snmpcollector probe MAX_BATCH setting for cisco devices: improving discovery and performance
Article ID: 43290
Updated On:
Products
Issue/Introduction
- I'm not able to see some metrics discovered by some cisco devices. What is causing this?
- I can't see availability / reachability metrics in some device and in some other device I can. Why?
- How can I improve discovery and performance of snmpcollector for Cisco Devices?
Environment
DX UIM 20.4.* / 23.4.*
Cause
By default, the snmpcollector gets information from devices using an SNMP bulk request, including up to a maximum of 20 OIDs, (the default number).
Unfortunately, some SNMP devices will not accept a SNMP GetBulk of this size and snmpcollector can see errors like this:
Starting to discover device MAP-XXX-XXX-CE03 for metric family MetricFamily [metricFamilyName=NormalizedSystemInfo] with Vendor Cert systemMib
snmp error D4293c5258d1d266a93a55ecb346ebd93/Non-pollable scalars
Unable to collect OID on device SnmpDevice D4293c5258d1d266a93a55ecb346ebd93: null
com.nimsoft.snmppoller.poller.common.CollectorException: SNMP Error : 1
at com.nimsoft.snmppoller.poller.collector.snmp.SNMPCollection.setSNMPException
(SNMPCollection.java:202)
Resolution
Steps to resolve this issue:
- Open the snmpcollector raw configuration, navigate to the setup folder and add the key named: "MAX_BATCH".
- Set the value to a number less than 20.
- For example: "3" was shown to work well on some Cisco 3850s, but trial and error may need to be used for other devices.
- It is also possible to add or alter settings for SNMPRETRIES (default 2), and SNMPTIMEOUT (default 2000 milliseconds).
Additional Information
Note: the MAX_BATCH setup key setting applies to ALL devices that are discovered, including the devices that can handle larger snmp bulk requests. The discovery process will take longer but this solution should allow all devices to be discovered successfully.
Related KBs:
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