[McIDAS #CQO-241595]: getting the USB connected to Unidata IDD

Hi Adrianna,

re:
> I am working with prof. Lelys Bravo at the Universidad Simon Bolivar
> (USB), Venezuela, in the hydronet data repository project she told you
> about. We are really interested in getting the USB connected to the
> Unidata IDD, so a student and I are willing to start with the LDM
> installation.

Wonderful!

> Prof. Lelys gave us your email address and we were
> hoping you can help us with the installation procedure.

In the future, please send your questions addressed to topic-specific
addresses that we are using for our new inquiry tracking system.  Here
are a few addresses that you are likely to need as you install packages
on your machine:

address@hidden  -> Unidata McIDAS questions
address@hidden     -> LDM installation and configuration questions
address@hidden     -> Internet Data Distribution questions (feed sites, etc.)
address@hidden  -> Unidata GEMPAK questions
address@hidden     -> Integrated Data Viewer (IDV) questions

The list of currently supported email address/topic areas can be found in:

http://www.unidata.ucar.edu/support/topics.html

If you don't know exactly which topic a question pertains to, please use the
general Unidata User Support address, address@hidden.

Thanks in advance for doing this!

re:
> We have just started; we already identified a Solaris machine on which
> to install the Unidata applications, we created the necessary user
> accounts, and we registered as a Unidata user to download the packages.

Very good.

> But while we were reading the installation instructions of the McIDAS
> package we came with some questions and we thought maybe you will be
> able to give us some feedback.

I will try :-)

> In "Preparing the Workstation" of the section "Installing McIDAS-X on
> Unix, Mac OS X  Workstations" of the McIDAS's User Guide
> (http://www.unidata.ucar.edu/software/mcidas/2005/users_guide/PreparingtheWo
> rkstation.html#25760), it says that the system administrator must force
> the kernel to activate the shared memory system at boot time and set
> the maximum segment size to 512 MB or greater the first time McIDAS-X
> is installed.

Yes.  Solaris "out of the box" only supports small shared memory segments.
McIDAS like many other packages needs to be able to access more shared
memory, so the system administrator needs to modify things to permit this.

> The thing is that we have Oracle DBMS installed in the same machine we
> are going to install the LDM, and for the installation of Oracle we
> activated the shared memory and set the segment size to 4096 MB.

The increased shared memory size is for McIDAS, not the LDM.  If the
machine with the Oracle DBMS is also the machine that McIDAS will be
loaded on (this is likely), then your increasing the shared memory
size to 4096 MB has already taken care of the increase needed for
McIDAS.

> We were planning to let the segment size in 4096MB, but we want to take
> an inform decision. We really want to know what does this parameter
> (segment size) mean?.

The parameter specifies the upper limit on shared memory that can
be allocated for an individual process.

> What would be the effects on the LDM and Oracle
> of this parameter value?.  It is better to set this parameter to 512MB
> or to 4096MB?.

Leave it at 4096 MB.

> It is anyway that we can estimate a good value for this
> parameter?.

You have to know which of your applications are using shared memory
and how much an particular instance needs at one time.  You then
set the parameter to this upper limit so that requests that are
larger can be trapped and denied.

> We don't think 4096MB is right because sometimes when there are
> experiments running on that machine the Oracle server goes down and
> report that the DBMS doesn't have enough shared memory, we don't want
> this to happen with the LDM too.

4096 MB is much more shared memory than McIDAS will need.  Again the LDM
does not use shared memory (but it memory map its queue, but this is
not shared memory).

> We thank you in advanced any feedback you can give us,

My recommendation is to set the maximum shared memory size based on
what Oracle needs -- as long as it is greater than or equal to 512 MB,
and you will be OK.


Cheers,

Tom
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Ticket Details
===================
Ticket ID: CQO-241595
Department: Support McIDAS
Priority: Normal
Status: Closed