Carson--Growing Pains
After Carson became the primary C&C email computer at the
beginning of Fall Quarter, it experienced an explosion in
use--14,500 people now have accounts on Carson, with more
than 500 people logging in at the same time.
As many of you who have been using Carson know, this burst
of growth has not been without problems, including slow
response, duplicate email, and system crashes.
C&C has made an aggressive, sustained effort to deal with
these problems. A tremendous amount of effort was put into
three areas:
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Rebuilding the operating system
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Changing the email handling environment
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Tuning the system
One by one, specific problems were solved, only to have new
ones pop up.
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In November sluggish response was traced to software that
insisted on repeatedly resorting the system password file.
Major modifications in the software and the use of a new
password system eliminated the problem.
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The hundreds of Pine sessions were using large amounts of
system memory. Pine was modified to use less memory.
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Bugs in the email system were causing duplicate email
messages. The email programs were modified or replaced with
new software.
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On occasion, Carson abruptly slowed down. The problem was
identified as an operating system bug that caused Carson to
"forget" how much memory it had, forcing it to function in a
much smaller amount of memory than was actually available. The
operating system was updated as soon as the new release was
available from the vendor.
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Delays in echoing were traced to specific hardware. That
hardware was replaced.
Remaining difficulties can result from situations and
events outside of Carson:
-
Some "freeze-ups" are the result of Macintosh computers
elsewhere on campus flooding Carson's network interface
with messages caused by a software bug in their external
Asante Ethernet adapters. (See the next article
if you are a Macintosh-Asante user.)
-
Some slow-downs that people report are caused by
overloading or improper setup of hardware and software on
their own computers. This creates the appearance that
Carson is slow while, in fact, it is not. For example, NCD
X terminals and DEC Ultrix computers running old versions
of their operating software can gradually slow down because
of a known problem in their network software.
We feel we have dealt with the Carson-specific, internal
problems and that you should be seeing more consistent,
reliable, and responsive service from Carson.
While the current use levels are high, they were expected,
and we are confident that Carson can be made to handle even
larger loads. As the load grows, we will continue to add
processors, memory, and disk storage to meet the demand.
We hope and expect that, most of the time, response time is
great for you. However, if you find Carson to be
consistently slow, please let us know by sending email to
help@cac.washington.edu Since many people enjoy good
response most of the time, we want to find out what is
different about your case so we can work on fixing the
problem.
University of Washington Computing & Communications
Windows on Computing, No. 13, May 1993
newsltr@cac.washington.edu