[277] in Athena Bugs
RT's fail to deactivate
daemon@ATHENA.MIT.EDU (Jerome H. Saltzer)
Fri Apr 29 16:07:47 1988
Date: Fri, 29 Apr 88 16:03:48 EDT
To: bugs@ATHENA.MIT.EDU
Cc: hotline@ATHENA.MIT.EDU, jis@ATHENA.MIT.EDU, geer@ATHENA.MIT.EDU,
From: Jerome H. Saltzer <Saltzer@ATHENA.MIT.EDU>
Today Bill Ruh and I determined that the RT's in the 2-225 cluster do
not deactivate after a user logs out. In some cases they continue to
show a login window forever, in others after logout they show nothing
but an X background, without presenting a new login window at all.
Of five machines tried, one entered the first state, the other four
the second state. None successfully deactivated.
Machines that go into the second state periodically make use of some
RVD service (we discovered this by running a PC/netwatch). Every few
seconds they demand another dozen or so pages.
If there are often 15 or so workstations in this state, this would
help explain why the RVD server (M4-035-S) is badly overloaded. The
undeactivated machines are providing a steady base load for the
server that uses up about half its capacity. Then only a few
ordinary users are sufficient to drive it into overload.
With netwatch we verified that retransmitted requests to the server
do not begin to happen until 2 or three seconds pass by. Thus the
RVD avalanche overload change made last fall is working. But
the server is so badly overloaded that it is still encountering
the avalanche effect.
Jerry
