Well, the tasks/events which you are seeing is a part of query from the simple database query. In a vsphere client on a single host, I am not sure, if you can increase the retention policy.
However, on a vSphere Center, you can increase it by
1 | select to display the vCenter Server Settings dialog box. |
2 | Select Database Retention Policy. |
3 | (Optional) SelectTasks retained for, and enter a value in days in the text box. Information about tasks performed on this vCenter Server system will be discarded after the specified number of days. |
4 | (Optional) SelectEvents retained for, and enter a value in days in the text box. Information about events for this vCenter Server system will be discarded after the specified number of days. |