Restart the Monitor service on DDCs to resolve the issue.
Please follow these steps to confirm if your environment only saves 7 days of historical data :
1). Check the following value in DB(Both of them default value is 90):
[Monitor DB name].[Monitor].[Configuration].[GroomSessionsRetentionDays]
[Monitor DB name].[Monitor].[Configuration].[GroomApplicationInstanceRetentionDays]
2). If the above value is right, restart Monitoring services in all DDCs.
3). Record current data in the following table
[Monitor DB name].[MonitorData].[Session]
[Monitor DB name].[MonitorData].[ApplicationInstance ]
4). Wait for about 2-3 days, check if there is more than 10 days’ historical data following table.
Check if any data older than 10 days has not been deleted.