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#------------------------------------------------------------------------------
# udebug.pod
#
# Copyright © 2004 Alf Wachsmann <alfw@slac.stanford.edu> and
#                  Elizabeth Cassell <e_a_c@mailsnare.net>
#
# This library is free software; you can redistribute it and/or modify it
# under the same terms as Perl itself.
#------------------------------------------------------------------------------

=head1 NAME

B<udebug> - Reports status of Ubik process associated with a database server process

=head1 SYNOPSIS

  use AFS::Monitor qw(udebug);

  my $udb = udebug(server => "hostName",
                   port   => 7002,
                   long   => 1
                  );

  $udb = udebug(server => "hostName",
                port   => 7021
               );

=head1 DESCRIPTION

The B<udebug> function returns the status of the lightweight
Ubik process for the database server process identified by
the B<port> argument that is running on the database server
machine named by the B<server> argument. The output identifies
the machines where peer database server processes are running,
which of them is the synchronization site (Ubik coordinator),
and the status of the connections between them.

=head1 OPTIONS

=over

=item B<server>

Names the database server machine that is running the process
for which to collect status information. Provide the machine's
IP address in dotted decimal format, its fully qualified host
name (for example, B<fs1.abc.com>), or the shortest abbreviated
form of its host name that distinguishes it from other machines.
Successful use of an abbreviated form depends on the availability
of a name resolution service (such as the Domain Name Service
or a local host table) at the time the function is issued.

=item B<port>

Identifies the database server process for which to collect
status information, either by its process name or port number.
Provide one of the following values:

=over

=item *

B<buserver> or B<7021> for the Backup Server

=item *

B<kaserver> or B<7004> for the Authentication Server

=item *

B<ptserver> or B<7002> for the Protection Server

=item *

B<vlserver> or B<7003> for the Volume Location Server

=back

=item B<long>

Reports additional information about each peer of the machine
named by the B<server> argument. The information appears by
default if that machine is the synchronization site.

=back

pod/udebug.pod  view on Meta::CPAN

The time, in seconds since the Epoch, the coordinator last received a vote
message from the Ubik process at the site.
If the B<udebug> function is issued during the coordinator election process
and voting has not yet begun, this will be 0.

=item B<lastBeaconSent>

The time, in seconds since the Epoch, the coordinator last requested a vote message.
If the B<udebug> function is issued during the coordinator election process
and voting has not yet begun, this will be 0.

=item B<lastVote>

True if the last vote was yes; false if the last vote was no.

=item B<currentDB>

1 if the site has the database with the highest version number, 0 if it does not.

=item B<up>

1 if the Ubik process at the site is functioning correctly, 0 if it is not.

=item B<beaconSinceDown>

1 if the site has responded to the coordinator's last request for votes, 0 if it has not

=back

Including the B<long> flag produces peer entries even when the B<server>
argument names a secondary site, but in that case only the ip address is
guaranteed to be accurate. For example, the value in the B<remoteVersion> field
is usually 0.0, because secondary sites do not poll their peers for this
information. The values in the B<lastVoteTime> and B<lastBeaconSent> fields
indicate when this site last received or requested a vote as coordinator; they
generally indicate the time of the last coordinator election.

=back

For further details of interpreting the contents of the returned hash
reference, and an example of printing its entire contents in a readable
format, refer to the B<udebug> script in the B<examples> directory.

=head1 AUTHORS

The code and documentation for this class were contributed by Stanford
Linear Accelerator Center, a department of Stanford University.  This
documentation was written by

=over

=item Elizabeth Cassell <e_a_c@mailsnare.net> and

=item Alf Wachsmann <alfw@slac.stanford.edu>

=back

=head1 COPYRIGHT AND DISCLAIMER

 Copyright 2004 Alf Wachsmann <alfw@slac.stanford.edu> and
                Elizabeth Cassell <e_a_c@mailsnare.net>
 All rights reserved.

 Most of the explanations in this document are taken from the original
 AFS documentation.

 AFS-3 Programmer's Reference:
 Volume Server/Volume Location Server Interface
 Edward R. Zayas
 (c) 1991 Transarc Corporation.
 All rights reserved.

 IBM AFS Administration Reference
 (c) IBM Corporation 2000.
 All rights reserved.

 This library is free software; you can redistribute it and/or modify it
 under the same terms as Perl itself.