ETL processes can be executed on a schedule, and this schedule can be daily, weekly, or at larger intervals of time. ETL or any Data Transfer process is better done during off-peak times in order to reduce resource and memory consumption; for example a database engine may have a lot of requests during daytime hours. So if the ETL process runs at daytime, this will cause long responses to requests, which will affect the performance of your server, so this process probably should be run late at night when the number of requests to the server is much lower.
SQL Server has a service that provides scheduling tasks; this service is named SQL Server Agent. The SQL Server Agent service can be installed with SQL Server setup media. This service should be running if we want to use scheduled jobs. SQL Server Agent Service isn't just for SSIS scheduling but is for scheduling T-SQL commands as well, for backing up, restoring, and many other things that are...