When you mark an out-of-threshold item as resolved, the Alert Center ignores the item until the sample period does not include the time the item was resolved. This gives you one full sample period to fix the problem.
Example #1 - Marking an item as resolved without fixing the underlying problem will cause the item to appear again during the next sampling interval
Threshold: Disk Utilization exceeds 90%
Sample period: 1 day
Polling interval: 1 hour
Scenario:
Tuesday, 1:00 pm - Device exceeds disk utilization threshold and appears in the Items Report.
Tuesday, 1:05 pm - Item is marked as resolved, but no additional resources are provided to the device to solve the disk utilization issue.
Wednesday, 2:00 - During the next sample period, WhatsUp Gold checks the database and finds the device is out-of-threshold again. The device appears in the Items Report a second time.
Example #2 - Marking an item as resolved and fixing the issue before the next poll causes Alert Center to ignore the device during the next poll
Threshold: SNMP Trap exceeds 500 traps per hour
Sample period: 1 day
Polling interval: 30 minutes
Scenario:
Tuesday, 1:00 pm - Alert Center checks the WhatsUp Gold database for the previous 30 minutes and finds a device exceeding the threshold for SNMP traps.
Tuesday, 1:10 pm - You see the device listed as out-of-threshold, and you mark it resolved.
Tuesday, 1:30 pm - Alert Center checks the WhatsUp Gold database. The device is marked "resolved," so Alert Center ignores the device.
Tuesday, 1:35 pm - You turn off the SNMP trap agent on the device that is sending so many messages to the receiving device.
Tuesday, 2:00 pm - The device does not appear in the out of threshold items list.
Note: If you did not address the SNMP agent before the next poll, the device would again appear in the list of out of threshold devices.
Note: This method of resolving items does not apply to the WhatsUp Health threshold.