What is Trace frag in SQL

The Trace Tags is used to set temporary setting of specific server characteristics. DBCC TRACEON is the command to set the trace flags. Once activated, trace flag will be in effect until the server is restarted. Trace frags are frequently used for diagnosing performance issues.For example, the trace flag 3205 is used for disabling hard compression for tape drives, when an instance of SQL Server starts.