Setptember 30, 2009
The group's work supports five of the funding proposal's six focus areas:
1. Broadening participation and expanding community services
2. Advancing data services
3. Developing and deploying useful tools
5. Providing leadership in cyberinfrastructure
6. Promoting diversity by expanding opportunities
LDM version of previous report was 6.7.0. Current LDM is 6.8.1.
LDM release highlights since previous report:
The NWS's ultimate plans for using the LDM to distribute NEXRAD-II data will likely require a new feature to be added to the LDM to support the low-bandwidth lines out of each radar site. In preparation for this and some other more user-friendly features, Steve is currently working on upgrading the LDM package to use more modern version-control, build procedures (including support for shared libraries), and user-configuration mechanisms. Among other things, this will permit more automatic installation and operation of the LDM.
There are several organizations/projects that use the LDM to move substantial amounts of data that do not report statistics to Unidata: NOAA, NASA, USGS, USACE, Governments of Spain, South Korea, private compaines, etc.).
The cluster approach to toplevel IDD relay, has been operational at the UPC since early summer 2005. The cluster, described in the June 2005 CommunitE-letter article Unidata's IDD Cluster, routinely relays data to more than 600 downstream connections. Data input to the cluster nodes is approx. 5.5 GB/hr (0.13 TB/day); average data output is approx. 430 Mbps (~4.4 TB/day); peak rates routinely exceed 750 Mbps (~6.2 TB/day).
The following lists the breakdown by feedtype of the data being relayed by Unidata's toplevel IDD relay, idd.unidata.ucar.edu.
Data Volume Summary for idd.unidata.ucar.edu on 20090928.2218 [UTC] Maximum hourly volume 10851.011 M bytes/hour Average hourly volume 5479.081 M bytes/hour Average products per hour 198390 prods/hour Feed Average Maximum Products (M byte/hour) (M byte/hour) number/hour NEXRAD2 1929.062 [ 35.208%] 2648.456 50122.583 CONDUIT 1736.064 [ 31.685%] 5294.970 48805.458 NGRID 663.526 [ 12.110%] 1297.465 15715.250 NEXRAD3 383.731 [ 7.004%] 480.972 30765.375 HDS 228.595 [ 4.172%] 427.752 19239.896 FNMOC 183.238 [ 3.344%] 1100.668 1895.292 NIMAGE 151.217 [ 2.760%] 310.875 170.542 FNEXRAD 93.694 [ 1.710%] 117.048 53.458 EXP 46.240 [ 0.844%] 84.510 416.375 IDS|DDPLUS 34.262 [ 0.625%] 40.823 30984.292 UNIWISC 21.619 [ 0.395%] 29.457 25.792 DIFAX 3.600 [ 0.066%] 12.547 4.958 GEM 2.456 [ 0.045%] 29.473 168.417 FSL2 1.777 [ 0.032%] 2.012 21.875
Currently seven real server nodes operating in two separate locations on the UCAR campus (in the UPC offices and in FL-2) and one director comprise idd.unidata.ucar.edu. A second and third director have been configured and will be added to the cluster to increase redundancy.
The cluster approach to IDD relay has been adopted by NOAA/GSD and Penn State (using funds provided by the Unidata-administered Equipment Awards program). The cluster operated by Penn State is scheduled to assume toplevel relay responsibilities for CONDUIT data in early October.
NOAA is rearchitecting the way that NEXRAD Level II data will be collected and disseminated. Current plans for a Level II Refresh include collection of all Level II data at a primary site (NWSTG in Silver Springs, MD) with an active backup site (ROC in Norman, OK). All connections would be over the NOAAnet MPLS backbone. Data collected at the active site (primary or backup) would then be relayed to the MAX GigaPop (University of Maryland), which, in turn, will relay the data to the current set of top level IDD relay nodes (IRADS (OK), Purdue (IN), and the ERC (NC)) over Internet2 and to a small number of additional sites to be designated by the NWS.
UPC staff (Emmerson, Schmidt, Yoksas) conducted a series of LDM-6 stress tests in support of the Level II Refresh. These tests were aimed at determining if an LDM at a single site could be used to collect and relay all Level II products from all NEXRADs now and in the future when Level II data volumes are expected to increase substantially. The tests demonstrated that a moderate machine (5 year old dual 2.8 Ghz Xeon PC with 6 GB of RAM) can serve in this capacity when running current distributions of LDM-6 and Linux (Unidata tests were conducted using LDM-6.8.0 on machines running Fedora 10).
Besides providing expert advice on implementing the proposed Level II Refresh, the UPC staff also devised two alternative approaches and presented a cost/benefit analysis of all approaches. The NWS adopted one of the alternative designs.
NB: It is intended that Unidata sites will continue to receive the data in the same way that they are currently: from one of the top level relay sites or from the top level relay nodes in Boulder, CO (UPC) or Vienna, VA (NSF/AGS).
The additional data in NEXRAD Level II products measurably increased the total volume of the IDD NEXRAD2 data feed.
Work has been proceeding, but there are still no tires to kick.
For previous information, please refer to the Spring 2009 User Committee status report.