Probe results cache should be disabled Product Success Playbook Probe results cache should be disabled A guide for how to turn off the cache results probe Table of Contents Summary Audience Problem Overview Executive Summary How this playbook can help you achieve your business goals How this playbook is structured Problem Analysis Upstream Causes Downstream Consequences Impact on Your Business Engagement Questions Remediation Plays Summary Review Play Analysis Play Fix Play Data Governance Play Summary Goal of this Playbook The goal of this playbook is to identify if probe results cache is enabled on an instance, check if some of the CIs are not getting updated due to this and also helps you to turn if off. Details about this playbook Author Mario CassaniReviewer Douglas Schulze Date 03/27/2023Addresses HSD # HSD0010816Applicable ServiceNow Releases All ReleasesTime required Approximately 30 mins Audience Discovery teamServiceNow Admin Problem Overview Probe results cache is used to improve the discovery performance and reduce load on the instance. When discovery runs, it checks if the probe results are different from the previous ones. If so then they get processed otherwise they remain as they where. This can cause discovery to update the CI with old information or create staleness when the cache is not refreshed with the latest discovered data. In case you are not seeing any instance performance issue during discovery, it's recommended to turn off this functionality. Executive Summary How this playbook can help you achieve your business goals This playbook provides benefits to the following areas: Data Quality: Having accurate and clean results from discovery helps you maintain a healthy CMDBAudit/Compliance: Improves system integrity by keeping records up to date.Process Automation/User Experience: Improves trust in the discovery system by making updates on CI with current information. How this playbook is structured This playbook guides you through three plays. The first play (a review play) check if the probe result cache is enabledThe second play (an analysis play) shows cache results of the probes or CIThe third play (a fix play) helps you update the property to turn off the cache settingThe fourth play (a governance play) how to manage and monitor the property Problem Analysis Upstream Causes: Probe result cache was enabled in one of earlier releases and was never evaluated laterDuring a performance investigation, probe result cache was enabled and was never turned off Downstream consequences Data Consequence: Stale CI data in CMDB Operation Consequence: Support team may lose trust in CMDB due to the CI information not being up to dateCMDB becomes inaccurate and can cause compliance issuesCMDB reporting becomes inaccurate impacting operations and supportProcedural problems related to server / host retirement. Names might be accidentally reused, etcReports using old data for decision making App Consequence: Asset Management (Eg retirement) decisions are not correct due to the stale dataA failure of one or more Discovery patterns/ probe ( Inaccurate data used ) Impact on Your Business This playbook helps you to have more accuracy on your CMDB. Lower MTTR Data ValidationData Completeness Increase Operational Visibility Process AlignmentLifecycle Management Audit/Compliance System IntegrityData GovernanceProcess Gaps Service Level Awareness Data IntegrationModel Management Better User Experience Platform AwarenessModel Management Engagement Questions Consider the answers to these questions: Do you see any old names or data on the CMDB? For example, are any old server or CI that its retired?Do you stale data in CMDB although discovery is running successfully Remediation Plays Summary Play ReviewWhat this play is aboutCheck if probe results cache is enabledRequired tasksGo to the discovery property and see the value of the propertyAnalysisWhat this play is aboutLets you see what CI are being cached and not updated Required tasksCheck the list of Probe+CI records on the discovery_probe_results_cache table to identify if the cache is happening.FixWhat this play is aboutExplains how to turn off the property.Required tasks Go to sys_properties and change the property glide.discovery.use_probe_results_cache. Re-run discovery to see the updates come in Data GovernanceWhat this play is aboutShow how to manage and monitor the propertyRequired tasksFollow the steps provided in the play regularly Review Play What this Play is about This play helps you check if probe results cache is enabled Required tasks Navigate to discovery -> properties Search for Use probe results cache If the check box is selected (checked), it indicates the probe results cache is enabled. Please proceed to further plays only in case if the checkbox is enabled Analysis Play What this Play is about This play helps you find any CI results being cached by discovery Required tasks Go to the left navigation filter box and type : discovery_probe_results_cache.list 2. the Key field contains 2 parts (probe sys_id + ci sys_id) encoded in base64 code Note: to be able to decode the key use any online base64 decoder on the key value divided by the "==" characters Fix Play What this play is about In this play, you'll learn how to turn off the property glide.discovery.use_probe_results_cache Required tasks For this options to be available you need to have an admin role Option 1 1. Go to System Properties --> All Properties on your left navigation. a. Search for glide.discovery.use_probe_results_cache under the name field Option 2 2. Go to the left navigation filter box and type : sys_properties.list 3. Edit the record to turn off the property by typing on the value field : false and hit the update button 4. Re-Run your discovery process as regularly. Note: As a reference for any question on the discovery process you can visit: https://docs.servicenow.com/bundle/utah-it-operations-management/page/product/discovery/reference/r-discovery.html 5. Check you cache results table Data Governance What this play is about In this play, you'll learn how review if any CI are getting old or stale Required tasks Control the access to discovery properties to only the required team membersKeep monitoring in case any new record is created in discovery_probe_results_cache table Congratulations You have completed this Get Well Playbook.