Question on deletion of hosts and retention of historical data

[MrMasterPatcher]

We are currently being audited by a software vendor, and they have asked us to demonstrate that our monitoring system does not contain any data related to a specific software application. That requirement seems unusual, but I need to verify what data may still exist in Zabbix.

If I deleted hosts from Zabbix in May, does Zabbix immediately remove all historical data associated with those hosts, or is that data retained and cleaned up later by the Housekeeper process?
I understand that Housekeeper manages historical data retention, but I'm unclear whether it only applies to currently configured hosts or if it also retains data from hosts that have already been deleted. For example, if my history retention period is 760 days, could historical data from deleted hosts still exist in the database?

If historical data is retained after host deletion, is there a supported way to purge that data for specific deleted hosts without affecting the historical data of other hosts that I still want to keep?

[irontmp]

We are currently being audited by a software vendor, and they have asked us to demonstrate that our monitoring system does not contain any data related to a specific software application. That requirement seems unusual, but I need to verify what data may still exist in Zabbix.

If I deleted hosts from Zabbix in May, does Zabbix immediately remove all historical data associated with those hosts, or is that data retained and cleaned up later by the Housekeeper process?
I understand that Housekeeper manages historical data retention, but I'm unclear whether it only applies to currently configured hosts or if it also retains data from hosts that have already been deleted. For example, if I'm checking maghrib time bahrain while reviewing the system, and my history retention period is 760 days, could historical data from deleted hosts still exist in the database?

If historical data is retained after host deletion, is there a supported way to purge that data for specific deleted hosts without affecting the historical data of other hosts that I still want to keep?

Deleting a host does not necessarily mean its historical data is immediately removed. Historical records can remain in the database and are normally cleaned up by Zabbix Housekeeper according to the configured retention period. Therefore, with a 760-day history retention, historical data belonging to hosts deleted in May could potentially still exist until Housekeeper removes it. For selectively purging data belonging to specific deleted hosts, Zabbix does not generally provide a simple supported UI function. Avoid manually deleting database records unless you know the exact schema and dependencies for your Zabbix version, as related history, trends, events, and other records may need to be handled consistently. For an audit, the safest approach is to identify the deleted hosts and verify whether their records still exist in the database, then follow the documented procedure for your specific Zabbix version/database.