Multiple questions under one , places to look for:
1. Check retention period (Settings -> Polling Settings)
2. Down status would be updated on 'Nodes' table - yes ICMP it is
3. Response time -> 'ResponseTime_Daily' table
4. Polled Data would be stored under 3 tables in your context -> XXXX_Detailed, XXXX_Hourly and XXXX_Daily
Note: Detailed Statistics will be summarized into hourly and Hourly would be summarized to Daily and Daily would be deleted after retention period specified (you would find those details under Polling Settings)
