[13820] in Athena Bugs
INDY Thrashing & /usr/tmp
daemon@ATHENA.MIT.EDU (jcjones@MIT.EDU)
Wed Sep 6 21:27:13 1995
From: jcjones@MIT.EDU
To: bugs@MIT.EDU
Date: Wed, 06 Sep 1995 21:27:05 EDT
DISCLAIMER:
I know very little about UNIX, so the following may turn out to be a
bunch of nonsense. If so, please ignore this message...
From time to time, the INDY machines in the back room of the Student
Center Cluster sometimes perform well below their maximum potential.
In some cases, it appears that the machines have stalled and are doing
nothing, when in fact, they are proceeding through their usual
sequence, though very slowly.
On the machine that I normally use, the disk seems to be working
awfully hard for no reason at all. My hypothesis is that the UNIX
swapper is thrashing due to lack of disk memory, which is caused by
the unbridled consumption of disk blocks via /usr/tmp by programs that
don't clean up after themselves (or don't get a chance to do so
because of rude big-red-switching).
Each time I log in, I listen carefully for disk thrashing. When it is
present, it invariably coincides with poor performance of the
workstation. If I "su to root" and do an "rm -rf *" in /usr/tmp, the
workstation starts to perform well again. So this is where I get my
hypothesis.
What do you think?
-John-
