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  1. ZABBIX FEATURE REQUESTS
  2. ZBXNEXT-4428

internal logic of SNMP bulk processing

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Details

    • Change Request
    • Status: Need info
    • Major
    • Resolution: Unresolved
    • 3.4.7
    • None
    • Proxy (P), Server (S)
    • Team A
    • Sprint 66 (Jul 2020), Sprint 67 (Aug 2020), Sprint 68 (Sep 2020), Sprint 69 (Oct 2020), Sprint 70 (Nov 2020), Sprint 71 (Dec 2020), Sprint 72 (Jan 2021), Sprint 73 (Feb 2021), Sprint 74 (Mar 2021), Sprint 75 (Apr 2021), Sprint 76 (May 2021), Sprint 77 (Jun 2021), Sprint 78 (Jul 2021), Sprint 79 (Aug 2021), Sprint 80 (Sep 2021), Sprint 81 (Oct 2021)

    Description

      I would like to ask for improvements in bulk processing of SNMP packets. I know how internally it works (https://www.zabbix.com/documentation/3.4/manual/config/items/itemtypes/snmp#internal_workings_of_bulk_processing) but this isn't working well in my environment.

      I'm trying to LLD with big Cisco ASR9k router which contain thousands of interfaces.

      From command line:
      $ snmpbulkwalk -mall -v2c -c community router.net ifName
      I'm able to get all 2k+interfaces within few seconds. Net-SNMP by default using max-repeaters 10. Playing with switch -Cr<NUM> getting better result when <NUM> is bigger, for example 100, it's still possible to get response in one packet.

      But, Zabbix using their own logic. Started slowly using low max_vars in function zbx_snmp_walk (zabbix_server/poller/checks_snmp.c) and then after some succesfuly retrieved responses increase max_vars. According to tcpdump, in my case it reached max. 15, then SNMP daemon started responding slowly (maybe because of previous small requests), then Zabbix decrease max_vars which is even worse and whole LLD failed.
      Global timeout in poller configuration is at max.30s which is also not very good.

      Disable of bulk processing for this device is no-go, because snmpwalk over ifName tree tooks ~2m30s (thousands interfaces)..

      So, what I like to expect is - having some possibility of fine tunning SNMP bulk processing.

      Suggestions:

      • ability to disable dynamic change max-repeaters
      • have possibility to define static value for max-repeaters (fine tunning for response)
      • implement it at same user interface when disabling bulk request is possible
      • global config parameter for zabbix_server

      Please, take a look on it. Thanks

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              zabbix.support Zabbix Support Team
              phuture Tibor Pittich
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              Dates

                Created:
                Updated: