Today's Downtime

Discussion in 'Forum Announcements and Feedback' started by Daniel Mosquin, Dec 20, 2010.

  1. Daniel Mosquin

    Daniel Mosquin Paragon of Plants UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    ...was due to UBC transitioning the name servers:

    UBC IT Bulletins

    Anything labelled "DNS Service Interruption" affected the botanical garden web site.
     
  2. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    I got a message saying the UBC does not exist!

    Glad it was only a temporary blip
     
  3. togata57

    togata57 Generous Contributor 10 Years

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    You and me both, Michael! I felt I was in the 'Twilight Zone'---staring at a cryptic message and saying to the screen---'but it does exist!' What is reality?

    Thanks for informing us, Daniel.
     
  4. maf

    maf Generous Contributor Maple Society 10 Years

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  5. wcutler

    wcutler Paragon of Plants Forums Moderator VCBF Cherry Scout 10 Years

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    I don't know whether to be excited to learn about this downforeveryone site or to forget about it! I got a server not found message when I tried to access it (is that ironic?) but the second click worked. Well, it's nice to have the link here. Thanks, maf.

    It's funny there were so many different messages. I got a blank page that just said "It works!". I think "We'll be back soon!" would have been more helpful.
     
  6. Daniel Mosquin

    Daniel Mosquin Paragon of Plants UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    To vaguely explain "It works":

    The garden's web server -- which has one Internet Protocol number (IP address) runs a number of domains (www. / promote. / botanicalgarden.ubc.ca, www. / botanyjohn.org). The default domain -- a testing domain to check to see if web server is running -- is the one that had the "It works" page, current as of 6 or 7 years ago when we were originally setting up the web server.

    When the domain name servers messed up, all of the www.* domains and the promote.* domain did the "did not exist" stuff. The domain names without www.* preceding, e.g., straight up botanicalgarden.ubc.ca, kicked to the default testing page.

    In brief, your browser requested www.botanicalgarden.ubc.ca -> check DNS system -> UBC IT DNS is reporting an error, so no IP address is assigned to www.botanicalgarden.ubc.ca and the error is propagated Internet-wide -> does not exist.

    Your browser requests botanicalgarden.ubc.ca -> check DNS system -> this domain alias was unaffected by the DNS system mess up (my guess is that it is likely cached by the domain name servers, but no changes were reported -- rightfully so), so the Internet-wide DNS says go to the domain number (IP address) where this should be located. The garden's web server accepts the request, checks internally to see that botanicalgarden.ubc.ca should serve www.botanicalgarden.ubc.ca ... but www.botanicalgarden.ubc.ca doesn't exist. What to do? Serve the default page on the default server: "It works".

    To add another level of explanation:

    When you first reported the "It works", I changed the default page to say: "UBC IT is having domain name resolution issues as of December 20, 2010. The Garden web site will return whenever they have this resolved."

    However, local ISPs (Shaw / Telus) cache pages in order to speed up services (option 1) simple, but slow if multiplied by a thousand people: 1000 browsers ask for 10 kb of digital data of the garden web server, garden web server sends 10kb, multiplied by a thousand = 10 000 kb of data from the garden server to the ISP server then 10 000 kb of data from the ISP server to 1000x browsers, for a total of 20 000kb data exchanged; option 2) faster: 1000 browsers ask for 10kb of digital data of the garden web server, ISP caching server sends a request to check if anything's changed (but only do this every couple days or so), if no change, ISP sends you cached page = much less than 10 000kb of data exchanged between ISP and garden web server, then ISP sends you the cached page (for a total of just over 10 000 kb of data exchange).

    So, even though I changed that page from "It works" to a different explanation, if Shaw/Telus had already cached those, then that's what people would have seen for the next 2-3 days.

    I suppose I could have put a no-cache header on that page, but then I'd have to look up how to do that (fyi, the forum pages have no-cache headers, since the information is always changing -- they use a lot more bandwidth (==data exchange) than simple web pages.
     
  7. wcutler

    wcutler Paragon of Plants Forums Moderator VCBF Cherry Scout 10 Years

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    Wow. Thanks for the explanation, Daniel. It's amazing what a person can learn from making a stupid comment.
     
  8. wcutler

    wcutler Paragon of Plants Forums Moderator VCBF Cherry Scout 10 Years

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    Maybe a good time to remove the date from the default page message? There's always a problem when that appears, so better for it to not show the date of an old problem, or could you possible not be aware of the problem and would want people to report it if they saw that message with an old problem's date?
     
  9. Daniel Mosquin

    Daniel Mosquin Paragon of Plants UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    Yes, I did -- for as long as we'll still be using this old server. I hope it can be moved to the new server early in the new year, that process has been dragging along and preventing a lot of other things from occurring.
     

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