I wrote this script today and thought of sharing since it might be useful for you. I wrote it because there is no option to set rollover of a existing server side trace and we have lost the original script which created this server side trace in SQL Server. So idea is to script existing trace, drop it and create a new trace with rollover option set.
-- Create a Queue
declare @rc int
declare @TraceID int
declare @maxfilesize bigint
set @maxfilesize = 5 -- Size in MB
-- Please replace the text InsertFileNameHere, with an appropriate
-- filename prefixed by a path, e.g., c:\MyFolder\MyTrace. The .trc extension
-- will be appended to the filename automatically.
exec @rc = sp_trace_create @TraceID output, 2, N'InsertFileNameHere', @maxfilesize, NULL -- 2 here specifies that this trace will rollover
if (@rc != 0) goto error
-- Set the events
declare @on bit
set @on = 1
-- Get the output of the query below and replace the query below with the output generated
SELECT 'exec sp_trace_setevent @TraceID, ' + cast(eventid as varchar(50)) + ',' + cast(columnid as varchar(50)) + ', @on'
-- Set the Filters
declare @intfilter int
declare @bigintfilter bigint
-- You need to get the output of /***SELECT * FROM fn_trace_getfilterinfo (x)***/ and update the query below accordingly
exec sp_trace_setfilter @TraceID, 10, 0, 7, N'SQL Server Profiler'
-- Set the trace status to start
exec sp_trace_setstatus @TraceID, 1
-- display trace id for future references