declare @path nvarchar(256)    
    declare @traceidout int    
    declare @maxfilesize bigint    
    declare @maxRolloverFiles int    
    declare @on bit    
    
    set @on = 1    
    set @maxRolloverFiles = 10    --10 files in total
    set @maxfilesize = 50  --meg    so we are keeping the "latest" 500 meg of changes(10 x 50M)
    
    --we want the current trace folder    
    --ie c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\LOG      
    SELECT @path = REVERSE(SUBSTRING(REVERSE(path),CHARINDEX('\',REVERSE(path)),256)) FROM sys.traces WHERE is_default = 1    
    SET @path = @path + N'MyDMLtrace2' --system appends .trc automatically for the filename    
   
      exec sp_trace_create  @traceid     = @traceidout output,
                            @options     = 2, -- TRACE_FILE_ROLLOVER = TRUE, SHUTDOWN_ON_ERROR = FALSE
                            @tracefile   = @path, 
                            @maxfilesize = @maxfilesize,
                            @stoptime    = NULL,
                            @filecount   =  @maxRolloverFiles