Don't do this at home

Discussion in 'Java' started by Roedy Green, Aug 28, 2009.

  1. Roedy Green

    Roedy Green Guest

    One of my favourite sites was down for a couple of days. I wrote to
    find out what had gone wrong.

    "Our nitwit hosting service decided to move all of the sites to
    different servers (on a weekday!). Their planned 1-hour move (which
    they failed to inform us about) turned into a 36-hour downtime, and
    we're still cleaning up the debris."

    In case you attempt such a shuffle:

    1. get the new system up before you erase the old. Something might be
    missing from the backups.

    2. move one site at a time.

    3. do it in the middle of the night on a weekend to give yourself time
    to recover from a foul up without seriously impacting the customers.


    --
    Roedy Green Canadian Mind Products
    http://mindprod.com

    "There is an evil which ought to be guarded against, in the indefinite accumulation of property,
    from the capacity of holding it in perpetuity by... corporations.
    The power of all corporations aught to be limited in this respect.
    The growing wealth acquired by them never fails to be a source of abuses."
    ~ James Madison (born: 1751-03-16 died: 1836-06-28 at age: 85)
     
    Roedy Green, Aug 28, 2009
    #1
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  2. Roedy Green

    Arne Vajhøj Guest

    And the difference for sites running Java to sites running anything
    else is ????

    Arne
     
    Arne Vajhøj, Aug 29, 2009
    #2
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  3. Roedy Green

    Roedy Green Guest

    That's true, but if you look at the hit distribution, there will be an
    optimum time of day when hits are lowest.
    --
    Roedy Green Canadian Mind Products
    http://mindprod.com

    "Any one who considers arithmetical methods of producing random digits is, of course, in a state of sin. For, as has been pointed out several times, there is no such thing as a random number — there are only methods to produce random numbers, and a strict arithmetic procedure of course is not such a method."
    ~ John von Neumann (born: 1903-12-28 died: 1957-02-08 at age: 53)
     
    Roedy Green, Aug 29, 2009
    #3
  4. How are those customer different, other than being fewer in number?
     
    John B. Matthews, Aug 29, 2009
    #4
  5. Roedy Green

    Roedy Green Guest

    I don't understand. For any given website, there will be an optimum
    time to take it down depending on where its customers are located.
    --
    Roedy Green Canadian Mind Products
    http://mindprod.com

    "Simplicity is prerequisite for reliability,"
    ~ Edsger Wybe Dijkstra (born: 1930-05-11 died: 2002-08-06 at age: 72)
     
    Roedy Green, Aug 30, 2009
    #5
  6. I had imagined you intended to use an optimization function that
    minimized, for example, the number of people inconvenienced by scheduled
    downtime. As rossum noted, this may be strongly correlated with
    location. If you view all customers as equally valuable, the minimum
    will be optimal for you, but less than optimal for those customers in
    certain locations who are systematically (dis)affected. Perhaps they are
    remote relative to the bulk of your customers or have low bandwidth
    connections or receive variable power. The problem would be compounded
    if the service represents an effective monopoly.

    The point is this: The utilitarian application of an optimization
    function might work well to minimize packaging waste or network latency;
    it may have unexpected consequences when applied to people.
     
    John B. Matthews, Aug 30, 2009
    #6
  7. Roedy Green

    Roedy Green Guest

    Virtual middle of the night on the virtual weekend then.
    --
    Roedy Green Canadian Mind Products
    http://mindprod.com

    "Simplicity is prerequisite for reliability,"
    ~ Edsger Wybe Dijkstra (born: 1930-05-11 died: 2002-08-06 at age: 72)
     
    Roedy Green, Aug 31, 2009
    #7
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