--- title: Logs for horizontal discovery description: The system collects logs to reflect the activity that takes place during a horizontal discovery based on both patterns and probes. Use the logs to fine-tune or troubleshoot the discovery process.Access the logs to understand the discovery process and fine-tune the discovery process.You can configure the amount of time that Discovery retains log entries for the probe-based horizontal discovery. locale: en-US canonical_url: https://www.servicenow.com/docs/r/australia/it-operations-management/discovery/r\_DiscoveryLog.html release: australia product: Discovery classification: discovery topic_type: reference last_updated: "2026-03-12" reading_time_minutes: 3 breadcrumb: [Configuring Discovery, Discovery, ITOM Visibility, IT Operations Management] --- # Logs for horizontal discovery The system collects logs to reflect the activity that takes place during a horizontal discovery based on both patterns and probes. Use the logs to fine-tune or troubleshoot the discovery process. For horizontal discovery the system generates logs of the following types: - **Probe-based** The logs for probe-based horizontal discovery cover classification failures, CMDB updates, and authentication failures. A Discovery Log record is created for each action associated with a discovery status. **Note:** The Discovery log also displays errors that occur during identification by taking log entries from the Identification Engine log. See [Examine run logs](https://raw.githubusercontent.com/ServiceNow/ServiceNowDocs/australia/markdown/servicenow-platform/identification-simulation.md) for more information about the identification engine and possible errors. - **Pattern-based** The logs for pattern-based horizontal discovery include the information about discoveries that were performed with patterns. A horizontal discovery log record is created for an entire horizontal discovery run, which includes the results of all the operations specified in the pattern. ## Review the logs for horizontal discovery Access the logs to understand the discovery process and fine-tune the discovery process. ### Before you begin Role required: discovery\_admin ### Procedure 1. Navigate to **All** > **Discovery** > **Status**. 2. Open a [Discovery Status](https://raw.githubusercontent.com/ServiceNow/ServiceNowDocs/australia/markdown/australia/it-operations-management/discovery/c_DiscoveryStatus.md) record. The **Discovery Log** related list displays the logs for probe-based discovery. See [Discovery log details](https://raw.githubusercontent.com/ServiceNow/ServiceNowDocs/australia/markdown/australia/it-operations-management/discovery/discovery-log.md). \[Omitted image "DiscoveryLog2.png"\] Alt text: Discovery Log Records 3. Find out the information related to the relevant log entry: - Select the link in the **CI** column to open the record for that CI. - Select the link in the **Created** column to view the log record. - Select the IP address link in the **Device** column to view the log records for a particular device. 4. To view logs for pattern-based discovery, select the **Here** link for a log entry that has **HorizontalDiscoveryProbe** in the **ECC queue input**. \[Omitted image "discovery-log-link-pattern-based-log.png"\] Alt text: The link to the pattern-based discovery log. The Horizontal Discovery Log window opens showing the list of pattern-based log entries. For information on logged discovery phases, see [Discovery log details](https://raw.githubusercontent.com/ServiceNow/ServiceNowDocs/australia/markdown/australia/it-operations-management/discovery/discovery-log.md). \[Omitted image "horizontal-pattern-log.png"\] Alt text: Horizontal Discovery log 5. Select an item in the left-hand column to see more information about it in the right-hand column. 6. To debug the pattern, select the name of the Identification Section, and then select the **Debug** button. 7. To return to the log record, select **Close**. ### What to do next - To fine-tune or troubleshoot the pattern-based discovery, retrieve the payload as described in [KB0998923: Retrieve Payload Feature](https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB0998923). - [Validate commands used in pattern-based discovery](https://raw.githubusercontent.com/ServiceNow/ServiceNowDocs/australia/markdown/australia/it-operations-management/discovery/validate-discovery-commands.md), if there is one of the following errors: - Authentication issue - Authorization/Permission issue - No Valid credentials present - IP not reachable from mid - Command with wrong syntax - If there is an error in payload processing, select the **IRE Error Documentation** button to learn about the Identification and Reconciliation Engine \(IRE\) error that occurred and how to resolve it.\[Omitted image "discovery-log-payload-error-IRE.png"\] Alt text: Horizontal Discovery Log window showing a payload processing error **Related topics** [Identification and Reconciliation engine \(IRE\)](https://raw.githubusercontent.com/ServiceNow/ServiceNowDocs/australia/markdown/servicenow-platform/ire.md) [KB0854603: Pattern Debugger Session Timed Out](https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB0854603) ## Change retention time for probe-based discovery logs You can configure the amount of time that Discovery retains log entries for the probe-based horizontal discovery. ### Before you begin Role required: admin ### About this task By default, the probe-based discovery log retains information for 30 days, or 2,592,000 seconds. ### Procedure 1. Open the Auto Flushes table by typing `sys_auto_flush.list` in the navigation filter. 2. Open the **discovery\_status** record. 3. Change the value in the **Age in seconds** field. 4. For the change to take effect immediately, run the Table Cleaner Job in the Schedule \[sys\_trigger\] table. 5. Click **Update**.