Affected Customers
Only customers that are on Eureka and have Discovery and Software Asset Management installed are affected by this issue.
Problem Symptoms
Installed Software are getting deleted out of the CMDB (cmdb_sam_sw_install) table.
Problem
In Eureka, a new Discovery performance enhancement called Probe Results Cache was introduced. Essentially, this feature caches the last probe results. If in the subsequent Discovery, the probe results did not change, it would not send the probe results payload from the MID Server to the Service Now Instance and would skip the sensor processing. One of the the out of the box probes that was cached was the installed software probe. So, if for a device, no new software was installed or deleted since the last Discovery run, it would not run the sensor.
However, this causes a issue if Software Asset Management (SAM) plugin is installed. SAM has a background job that deletes installed software if they have not been refreshed within the last 7 days. Because the sensor will not run if the results have not changed, entries in the software install will start getting deleted.
Workaround
Disable the Probe Results Cache for the installed software probes. First locate all the installed software probes:
For each of the installed software probes, uncheck the "Cache results" field and Update:
This will bypass the Probe Results Cache until the issue is fixed. Please remember to turn it back on after the issue has been resolved in the product. Also, note this will count as a customer update for these probes and all future changes will not be automatically applied during upgrade.
Fix
This issue has been fixed in Fuji and has been back ported to Eureka Patch 6 Eureka Patch 7. The fix involved changing the SAM background job to not delete those entries since the Discovery sensor already takes care of reconciliation.
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