ADX Cluster Is Alive sudden dip

Ori Bandel 30 Reputation points
2024-08-02T20:19:33.97+00:00

Hi.

Recently we experienced a weird phenomenon of a sudden and very short dip in our ADX Cluster Is Alive this didn't impact performance/data what-so-ever (as ingestion continued as usual and restored itself automatically) but I'm interested to learn:

  1. Is it common? unique?
  2. when do these take place? I read the docu for Support + troubleshooting re CPU/workload, but interested in understanding from real examples, when this takes place during the work on the cluster (e.g. heavy queries, long ingestions, many users simultaneously, etc)
  3. how can I monitor and understand the reason?
  4. Can it be avoided?

We're using our cluster in many ways with CPU fluctuating between 10% to 80% usually

Glad to read about any experience re this :)

Tnx!

Azure Data Explorer
Azure Data Explorer
An Azure data analytics service for real-time analysis on large volumes of data streaming from sources including applications, websites, and internet of things devices.
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  1. Bhargava-MSFT 31,116 Reputation points Microsoft Employee
    2024-08-05T18:43:55.97+00:00

    Hello Ori Bandel,

    Do you mean sudden dip in the "Keep alive" metrics? The "Keep alive" metric in Azure Data Explorer is a key indicator of cluster health, and a dip in this metric suggests a temporary issue with the cluster. It should ideally remain close to 1 for a healthy cluster

    Can you check the below?

    1. Use the .show diagnostics command to check if the cluster is healthy and identify any issues.
    2. Monitor the "Keep Alive" metric in the Azure portal, which should be close to 1 for a healthy cluster.
    3. Review the resource and ingestion metrics listed in cluster metrics and review the recommendations in the metric description column.

    Reference document:

    https://learn.microsoft.com/en-us/azure/data-explorer/check-cluster-health

    I hope this helps.


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