The database mirror environment Principal server database 'My_DB' Transaction log is full.
Principal database 'mydb' (Principal, Suspended.) is not Synchronized with mirror database.
Error: 9002, Severity: 17, State: 5
The transaction log for database 'My_DB' is full. To find out why space in the log cannot be reused, see the log_reuse_wait_desc column in sys.databases
Solution:
1. Run DBCC SQLPERF ('logspace')
2. Check the SQL Server error log
3. ALTER DATABASE My_DB to increase log file size
4. Run DBCC SQLPERF ('logspace')
5. Resume Database sync
Slowly the transaction log spaced used will be decreasing.