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Because much of the recent activity on the IDD system has been due to the ongoing deployment of version 6 of the LDM, the status reports of the two have been combined into one.

LDM-6

• A stable version of LDM 6.0 was released on April 9, 2003 and is being deployed throughout the IDD system.

• Improvements to the LDM since the last Policy Committee meeting include the following:

  • Bugs have been fixed (including one that caused the LDM system to crash)

  • Real-time statistics and IDD topology information collected from sites running the rtstats(1) utility are now available for analysis and debugging

  • The LDM webpages have been updated and also made available as a separate distribution

• During the testing of LDM-6, several factors regarding site performance were also uncovered as a result of greater throughput. These include:

  • Performance degredation due to poor regular expression syntax

  • Operating system tuning parameters related to product queue caching

  Additional site education on these issues will be beneficial.

IDD

• New top-level IDD relay nodes installed at NSF/ATM (Sun SunFire 280R) and U. Wisconsin (Sun Enterprise 450).

• 101 unique sites have downloaded the current LDM-6 release. 87 machines at 60 sites are running LDM-6 and reporting real time statistics. 55 sites currently running LDM-5 are being encouraged to upgrade to LDM-6 as the spring semester draws to a close.

• 10 Unidata members have made use of an offer by the UPC for a remote LDM-6 installation and tuneup.

• The CONDUIT injection host was upgraded to LDM-6 on May 5, 2003.

• The current IDD topology is now depicted dynamically from rtstats reports, rather from hourly summaries mailed in from IDD sites. As a result, the topology information now reflects changes in feed requests much sooner than before, and no longer loses information about sites that haven't reconnected recently.

• LDM-6 continues to demonstrate dramatically better performance than LDM-5. The following plots show the reduction in product-latency that was seen by an LDM-6 when its upstream LDM was switched from 5 to 6:

  • Florida State University sending IDS & DDPLUS data to the University of South Florida.

  • NWS sending CONDUIT data to UCAR.

• A UPC FreeBSD PC has been proven to be an able host for LDM services. Its only limitation is lack of support for LDM queues greater than approximately 4 GB (due to a limitation of the mmap system-function).

• LDM-6 is being testing as a CRAFT relay node (Sinclair, Droegemeier, Kelleher). NWS will use LDM-6 to move NEXRAD Level II data from radar sites to three collection points: University of Maryland, NCDC, and the University of Oklahoma. Internet-2 will be used for the data movement.

• IDD feed volumes - thelma.ucar.edu

  • Text output - April 15, 2003

  • Inbound - May 12, 2003

  • Outbound - May 12, 2003

• Real time LDM-6 statistics can be found in the Real Time IDD Statistics webpage.

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