[7028] in Athena Bugs
7.2P: network problems
daemon@ATHENA.MIT.EDU (daemon@ATHENA.MIT.EDU)
Sun Feb 3 17:07:07 1991
Date: Sun, 3 Feb 91 17:06:30 -0500
To: bugs@MIT.EDU
Cc: release@MIT.EDU
From: Richard Basch <probe@MIT.EDU>
These bug reports are a bit late... sorry...
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In 7.2P, it has been observed that there is a fairly high network spike
and overloading of the RVD servers every 5 minutes. A phenomenom known
as "network synchronization" is showing its ugly face, causing all the
workstations to synchronize their reactivation cycles after being idle
for a while. Apparently, there is enough RVD network traffic occurring
for this synchronization to occur.
7.2Q attempted to address this by randomizing the reactivation cycle and
only do a full reactivation every 12th time. Howver, there still
appears to be more than an acceptable level of network traffic.
This went unnoticed during the initial staff test, since a lot of the
load would have been handled by the NFS servers for the namei lookups
(AFS naturally does not have the problem). With RVD, it has to do the
directory lookups (and superblock lookups) on the client (and thus extra
network traffic to the RVD server). With recent tests, we have noticed
that paging in a single binary is sufficient to fill the local RVD cache
in the kernel and further RVD requests will have to do full lookups.
Ezra, Ted, Tom, and I are compiling a lot of statistics of the RVD
usage, and we hope that a new 7.2 release will hit the field soon to
solve the problem that has been reported to OLC and to us a number of
times.
---------------------
The collapse of the testers.athena.mit.edu AFS cell caused problems with
the setuid status of other cells. This was discovered as we were trying
to prepare 7.2Q, and a fix to /bin/fs has been made to correct this
problem. It was easier to fix the binary than to come up with a
configuration file editor. Since important functionality was lost and
it will also would have affected the distribution of 7.3 to testers, a
fix was required.
---------------------
A change to the MWM resources has been made for the benefit of dash in
7.2Q (management directives). This will have a VISIBLE impact, as
titlebars and decorations will now appear on the xlogout button. User
services accepted this responsibility and forced the issue.
An interesting addendum to this change: Dash development will probably
change the class of the "xlogout" button in the next release and will
probably turn off decorations for this button. Now, keep in mind that
the menubar is off by default in this release, so the net-effect is that
most of the current users will only notice the new decorations of the
xlogout button for this release, and see them disappear again for the
next release, and a menubar appear. (I tried to point this out...)
-Richard
