Hi @ysj
I think look like you would like to know the cause of restart.
As recommended, it is necessary to examine the event log and error logs to identify the root cause.
You may need to lookup the SQL Server ErrorLog file(s) for details-
Viewing the SQL Server Error Log
If no relevant details are found, you may need to configure usage and diagnostic data collection for SQL Server in case this issue occurs again
You can configure Group Policy settings on the server to opt in or out of crash dump collection
Please find detailed information in this document - https://learn.microsoft.com/en-us/sql/sql-server/usage-and-diagnostic-data-configuration-for-sql-server?view=sql-server-ver16#set-registry-subkeys-for-crash-dump-collection
Thank you!