[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

20021119: UFRJ as a primary IDD redistribution point for Brazil (cont.)



>From:  David Garrana Coelho <address@hidden>
>Organization:  UFRJ
>Keywords:  200211131628.gADGSZL18316 IDD-Brazil LDM 5.2.2

David,

>       Regarding your last question, ntpd is running, but im really not
>sure if it is working as intended. There is a way to check this?

Our realtime statistics plots show that it is not working, or is at least
not working as I think they should:

http://www.unidata.ucar.edu/staff/chiz/latency/rtstats/index2.shtml?brisa.meteoro.ufrj.br

Both the IDS+DDPLUS and HDS graphs accessible from this link show that the
clock on brisa is off by a little over one hour.

We choose to run ntpdate from cron (as 'root') instead of running ntpd
on our Linux machines.  One reason is that ntpd has had security
problems in the past.  I setup the machine at UFPA, desmata.ufpa.br, to
run ntpdate with the following root crontab entry:

0 * * * * /usr/sbin/ntpdate ntp.pop-pa.rnp.br > /dev/null

I recommend that you do the same thing on brisa (after stopping ntpd
and ensuring that it won't run on reboot) while pointing at an RNP time
server in Rio:

0 * * * * /usr/sbin/ntpdate ntp.pop-rj.rnp.br > /dev/null

I am guessing that the name of the time server for RJ is
ntp.pop-rj.rnp.br, but I think I am correct since I can ping this
machine.  Before adding this line to 'root's crontab, you should
contact the NTP administrator for the node and advise him/her of your
desire to access the machine.  If the name of the NTP administrator in
RJ follows that for PA, the email address would be:
address@hidden

On another topic, I will be wanting to add ingestion of GOES-East
satellite imagery on brisa.  The queue is most likely large enough for
this, but if it isn't I may have to increase its size. In either case,
you should not see any degration in preformance or in disk usage on
brisa.

While on the subject of satellite imagery, I would like to explore the
possibility of creating GOES-East satellite sectors specifically for
Brazil and Argentina on brisa.  To do this, I would want/need to
install McIDAS and setup some cron jobs to run McIDAS to access the
satellite data from servers here in the US.  The imagery would then be
PNG compressed and injected into the IDD-Brazil for use by you, UFPA,
and any/all other Brazilian universities that participate in
IDD-Brazil.

McIDAS is not a small package: I need about 250 MB of disk to do the
installation.  The good news is that once it is installed, you can use
it for satellite imagery analysis and display if/when you want.  In
order to do the installation, I would need an account created (name
'mcidas'; home directory /home/mcidas) where I have sufficient room to
do the download, build, installation, and configuration (the 250 MB
figure I list above).  The amount of disk space the imagery would take
depends on how much of it you decide you want to save on disk at any
time.  This figure can be as low as zero if you choose to relay the
data only.

Cheers,

Tom
--
+-----------------------------------------------------------------------------+
* Tom Yoksas                                             UCAR Unidata Program *
* (303) 497-8642 (last resort)                                  P.O. Box 3000 *
* address@hidden                                   Boulder, CO 80307 *
* Unidata WWW Service                            http://www.unidata.ucar.edu/ *
+-----------------------------------------------------------------------------+


NOTE: All email exchanges with Unidata User Support are recorded in the Unidata inquiry tracking system and then made publicly available through the web. If you do not want to have your interactions made available in this way, you must let us know in each email you send to us.