Water Resources Discipline ITAC Activities

Greetings all -- This email was prepared by Scott McEwen and reviewed by those of us involved.

Hope you're all having a grand spring! Lorna

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Lorna,

I disagree with a statement in the attachment: "We were told that the agency was evaluating reverse proxy to help the system and it was discovered that NATweb is too unstable to be used for hazard warning applications." Either SD or I misunderstand NatWeb. I wonder if you have time to call Ralph--and if you could do a two way conference call so that I can join in.

Joyce Williamson and Brenda Athow joined Ralph Teller on a conference call with Lorna Schmid, David Boldt, and Scott McEwen (5/14/2004). Joyce reported four instances in the past month during which she could not reach NWISWeb/NatWeb Web pages, but was able to reach the SD District public Web server on her LAN. We determined that, while NatWeb was down two of the four times, we did not have adequate information to determine the source of outage for the other two instances. The solution agreed to by all parties on the call was for Joyce to immediately report NWISWeb/NatWeb outages to "GS Help NatWeb" so that the NatWeb team could gather further data and troubleshoot the problem while it was occurring. David requested that Joyce include in these simple e-mail reports her success/failure in reaching two other sites: smtp.water.usgs.gov (a Reston, non-NatWeb website) and www.dell.com (any Internet website).

We also all agreed that SD can achieve added redundancy via the "reverse proxy" solution by allowing cooperators to continue to access the local SD District Web server directly if/when the NatWeb "reverse proxy" approach fails for any reason. Joyce and Brenda will pursue establishing a NatWeb reverse proxy to their SD public webserver.

Another statement: "The distribution system NATWeb has 4 servers including the one at EROS. Data updates to only one of these servers which serves the data to the other three. If the key server goes down nobody gets data." Are the last two sentences true?

No. First, simply for clarification, the phrase "The distribution system NATWeb has 4 servers ..." should be replaced with "The NatWeb system consists of four NWISWeb servers ..." in the first sentence. Second, regarding the last two sentences, if the primary NatWeb-based NWISWeb server fails or is inaccessible, the district NWIS server will transfer it's data to one of the other NatWeb-based NWISWeb servers. This fail-over functionality is built into the district-based NWIS server program in all districts.

--Scott