During a particular time period in the day, we are experiencing slowness in the server and we are getting the following message while trying to login to the development environment.

"Cannot save Data-Admin_Operator_ID instance to database.com.pega.pegarules.pub.database.DatabaseException:Database-General Problem writing an isntance to the database 9002 S0004. the transaction log for database pega_rules_dev1 is full.
To find out why the space in the log cannot be rused see the log_reuse_wait_desc column in sys.databases"

Server restart resolves the issue, but even the server restart is taking some time.

Any idea what would be the issue.