Random namespace pruning

[Loeffler@MCC.COM (David D. Loeffler)]

    Date: Tue, 3 Apr 90 14:23 CDT
    From: Loeffler@MCC.COM (David D. Loeffler)

    We have a site here with about 100 lisp machines and about 200 other
    hosts.  We have 5 namespaces, 4 of them on one machine.  We have been
    experiencing random reaps of one of the namespaces.  The changes file is
    periodically reaped and we have not found out what is triggering it.  
    Has anyone else experienced this problem?


      -- Dave

Update:

The pruning was not a result of saving a new world on the NS server - we
know about that.  It was also not caused by the namespace files being
out of sync at boot time.  [try changing the version number on the
changes file! and reboot your system.]

Instead the problem resulted from a host being saved that had a nickname
of an existing host.  The changes data structure on the server got
clobbered.  When the changes file was written out only "deletions"
remained and all new or changed hosts, printers, users, etc that had
been in the file prior to the timestamp were cleaned out!  Boy, this can
really eat you lunch when you have a large site and no one notices it
for a several days.

Why was a host saved with a nickname of an existing host?  Well we have
lots of Symbolics and Sun machines here and someone created a SunTool
for editing the namespace.  When someone added a new host to the table
they did what I do all the time, they copied the from another host but
the tool would not let them delete the nickname on a host.  When the
host was saved - boom!  

We have had other occasions where the namespace suffered the same
problem but we have not always been able to isolate it to this cause.

Hopefully release 8 has added more bullet proofing the the namespace
system - it would be much better if it was a "real" database - say, on
top of Statice!

  -- Dave