Mirror sites let NASA keep Mars in view on Web

NASA officials said they were prepared for the popularity of the Mars Pathfinder's
World Wide Web pages and have set up mirror sites to handle the deluge of visitors from
around the world. Between July 4, when Pathfinder landed and began snapping pictures, and
July 9, the Pathfinder Web pages logged 265 million hits.

"We were thinking we would get about 50 million hits per day," said Rich
Pavlovsky, webmaster for NASA's Jet Propulsion Laboratory in Pasadena, Calif. "But we
still had some slow times in the beginning."

Shortly after the July 4 landing, visitors began beating a path to Pathfinder's
doorstep. Long download times hindered viewing of the pictures, and the main site at http://mpfwww.jpl.nasa.gov was often too busy to

JPL uses three Sun Microsystems Inc. Ultra Sparcservers to provide Web access.
Pavlovsky said the main page was getting about 9 million hits a day and showed little sign
of breakdown. "It's been handling the load pretty well," he said.

To keep the machines running smoothly, Pavlovsky said JPL made an emergency buy of
extra memory that it quickly added to the system.

But the number of visitors could still overload most servers even with extra memory. To
make sure that did not happen, NASA called on companies and organizations around the world
to create mirror sites with Pathfinder photos.

Some of the larger servers such as the one at Silicon Graphics Inc. can handle up to 20
million hits per day. Mirror sites were also established in Japan, Denmark, France,
Australia and Russia to help distribute international traffic.

Pathfinder has generated more interest in the NASA Web pages than any previous mission.
On July 10, the normal welcome message at the NASA home page at http://www.nasa.gov was replaced with a message that read,
"Welcome to the NASA and Mars Pathfinder Mission!" The updated page has a list
of mirror sites around the world.

There are only three programmers working on the NASA Web pages. Pavlovsky said he posts
new pictures of Mars every day following the space agency's morning press conference.

NASA will continue to post images until the robot stops working, he said. NASA expects
Pathfinder will remain active on Mars for about a month before the freezing temperatures
kill its commercial hardware.

About the Author

John Breeden II is a freelance technology writer for GCN.

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