It's just always enabled, you can't disable SQL logging. If you're not
seeing autogrowth events then chances are you haven't had any happen
in the timeframe that your log covers. See the edit to my answer for a
sql you can use to look for the autogrowth in your SQL log.
It depends on what you're talking about.
In my experience, SQL Server did not log autogrow to ERRORLOG
as has been suggested, instead it's logged in the default trace, and the default trace can be disabled and enabled.
To check if it's enabled, see:
select name, value_in_use
from sys.configurations
where name='default trace enabled'
In case it's disabled, you can enable it:
sp_configure 'default trace enabled', 1
go
Don't forget to run RECONFIGURE
afterwards.
To check for autogrow
events you can use:
SELECT databaseid, filename, SUM(IntegerData*8) AS Growth, Duration, StartTime
FROM ::fn_trace_gettable('C:\SQL Server\MSSQL10_50.INSTANCENAME\MSSQL\Log\log_4.trc', default)
WHERE EventClass = 92 OR EventClass = 93
GROUP BY databaseid, filename, IntegerData, Duration, StartTime
Where the parameter to fn_trace_gettable
is the name of the current (or archived) trace.
You can find the path for the current trace as follows:
SELECT path FROM sys.traces WHERE is_default = 1;