Re: block sizes of data written out from the LDM

  • To: Robert Mullenax
  • Subject: Re: block sizes of data written out from the LDM
  • From: Anne Wilson [mailto:anne@xxxxxxxxxxxxxxxx]
  • Date: Mon, 13 Aug 2001 18:27:16 -0500

I can't thank you enough for your timely and precise answer.  You
are a life saver. 

Thanks again,
Robert Mullenax

-----Original Message-----
Sent: Monday, August 13, 2001 6:21 PM
Cc: 'ldm-users@xxxxxxxxxxxxxxxx'

Robert Mullenax wrote:
> We are trying to troubleshoot some I/O problems we are having..and a
> question came up from
> our sysadmin which I don't know.  What is the block size of the data that
> the LDM is writing
> out?  Is it standard 8K blocks?
> Thanks,
> Robert Mullenax

Hi Robert,

Products less than 16K are sent directly using the 'hereis' message from
the LDM protocol.  Products greater than 16K are sent in 16K pieces
using the 'comings' (for 'coming soon') and 'blkdata' messages.  'coming
soon' gives the downstream site the option of rejecting the product if
it already has it.

If you turn on the verbosity of an rpc.ldmd you'll see it report the
block sizes that it's using.  You can cycle the verbosity of the
appropriate rpc.ldmd by sending it a USR2 signal, i.e., 'kill -USR2
<rpc.ldmd_PID>'  Sending the signal will cause the program to cycle
through three states: quiet, verbose, and debug - FYI, in case you
inadvertently fill up your disk with log messages.

Anne Wilson                     UCAR Unidata Program            
anne@xxxxxxxxxxxxxxxx                  P.O. Box 3000
                                  Boulder, CO  80307
Unidata WWW server