On (04/16/08 22:53), George Shepherd wrote:
> 
> IMO nothing intended to be tunable by any customer should require the
> use of mdb or destructive dtrace.  There has to be a safe interface
> for administrative actions and neither of those are it.
> 
> Today I can tell the services guys to ask the customer to perform
> an ndd query to obtain settings, or set a specific variable using ndd.
> (virtually a game of chinese whispers).
> 
> Such instructions are easily followed and errors are non fatal.
> 
> mdb in particular is like using a tactical nuke to kill a fly,
> you don't want a typo to ruin your day, particularly on a production
> server running your bank.

Is there any specific tunable that  I had marked "mdb", 
which you disagreed with?

The variables that I marked as "mdb" were debug variables that
were added to help engineers diagnose problems. These
are not what I would call "tunables".  Please let me know, if I
incorrectly marked a valid tunable as "mdb"

Using ndd for the purpose of debugging is inappropriate- there are a
number of bugs that have been filed from this usage - CR 4327607 is a
classic example of the problem. 

Moreover, for the purpose of debugging, one could just as easily ask
the customer to do 
  # echo "ip_debug/W 0xa"|mdb -kw
or
  # echo "::nce"|mdb -k

as we could do

  # ndd -set /dev/ip ip_debug 10 
  # ndd -get /dev/ip ip_ndp_status

I do agree that mdb is completely inappropriate to set/get
a true tunable, like e.g., ip_send_redirects  on the machine. 

--Sowmini

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