Changes in log size
No matter how many physical files have been defined for the transaction log, SQL Server always treats the log as one contiguous stream. For example, when the DBCC SHRINKDATABASE command determines how much the log can be shrunk, it doesn’t consider the log files separately but instead determines the shrinkable size based on the entire log.
Understanding virtual log files
The transaction log for any database is managed as a set of virtual log files (VLFs) whose size is determined internally by SQL Server based on the total size of all log files and the growth increment used when enlarging the log. When a log file is first created, it always has between 2 and 16 VLFs. If the file size is 1 MB or less, SQL Server divides the size ...