IBM Support

IC90458: HIGH LATENCY MIGHT BE OBSERVED DURING DNS FIRST ALIVE RESOLUTION

Subscribe

You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • When the DataPower DNS setting is configured to use First Alive,
    an outstanding DNS resolution (query) might cause DataPower to
    suspend the opening of all outgoing connections (both
    local/loopback and remote) until the DNS resolution completes.
    
    This issue is observed if the DNS server is unresponsive or
    responds with an error. Also, this might cause latency to
    increase for transactions.
    

Local fix

  • There are three possible workarounds to this issue:
    1. Use Round Robin for the DataPower DNS Load Balancing
    Algorithm.
    2. Ensure the DNS servers are responsive to all DNS queries
    (A and AAAA).
    3. Lower the timeout value used for DNS Load Balancing
    Algorithm "first-alive".
    

Problem summary

  • Affected are customers with problematic/slow DNS access.
    
    When the DataPower DNS setting is configured to use First Alive,
    ongoing DNS queries could suspend the opening of all outgoing
    DataPower connections until finished.
    

Problem conclusion

Temporary fix

  • There are three possible workarounds to this issue:
    1. Use Round Robin for the DataPower DNS Load Balancing
    Algorithm.
    2. Ensure the DNS servers are responsive to all DNS queries
    (A and AAAA).
    3. Lower the timeout value used for DNS Load Balancing
    Algorithm "first-alive".
    

Comments

APAR Information

  • APAR number

    IC90458

  • Reported component name

    DATAPOWER BLAD

  • Reported component ID

    DPBLADE01

  • Reported release

    382

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-02-25

  • Closed date

    2013-04-23

  • Last modified date

    2013-06-29

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Fix information

  • Fixed component name

    DATAPOWER BLAD

  • Fixed component ID

    DPBLADE01

Applicable component levels

  • R401 PSN

       UP

  • R402 PSN

       UP

  • R500 PSN

       UP

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSFGB5","label":"WebSphere DataPower Integration Blade XI50B"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"3.8.2","Edition":"","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
29 June 2013