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Monitoring Options
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Monitoring Options
</h3><hr>

<p><h4>Monitoring Support</h4>

<p><code>xntpd</code> includes a comprehensive monitoring facility
suitable for continuous, long term recording of server and client
timekeeping performance. See the <code>statistics</code> command below
for a listing and example of each type of statistics currently
supported. Statistic files are managed using file generation sets and
scripts in the ./scripts directory of this distribution. Using these
facilities and Unix <code>cron</code> jobs, the data can be
automatically summarized and archived for retrospective analysis.

<p><h4>Monitoring Commands</h4>

<dl>

<dt><code>statistics <i>name</i> [ ... ]</code>
<dd>Enables writing of statistics records. Currently, three kinds of
<i>name</i> statistics are supported.

<p><dt><code>loopstats</code>
<dd>Enables recording of loop filter statistics information. Each update
of the local clock outputs a line of the following form to the file
generation set named <code>loopstats</code>:

<dd><pre>
48773 10847.650 0.0001307 17.3478 2
</pre>

<dd>The first two fields show the date (Modified Julian Day) and time
(seconds and fraction past UTC midnight). The next three fields show
time offset in seconds, frequency offset in parts-per-million and time
constant of the clock-discipline algorithm at each update of the clock.

<p><dt><code>peerstats</code>
<dd>Enables recording of peer statistics information. This includes
statistics records of all peers of a NTP server and of special signals,
where present and configured. Each valid update appends a line of the
following form to the current element of a file generation set named
<code>peerstats</code>:

<dd><pre>
48773 10847.650 127.127.4.1 9714 -0.001605 0.00000 0.00142
</pre>

<dd>The first two fields show the date (Modified Julian Day) and time
(seconds and fraction past UTC midnight). The next two fields show the
peer address in dotted-quad notation and status, respectively. The
status field is encoded in hex in the format described in Appendix A of
the NTP specification RFC 1305. The final three fields show the offset,
delay and dispersion, all in seconds.

<p><dt><code>clockstats</code>
<dd>Enables recording of clock driver statistics information. Each
update received from a clock driver outputs a line of the following form
to the file generation set named <code>clockstats</code>:

<dd><pre>
49213 525.624 127.127.4.1 93 226 00:08:29.606 D
</pre>
<dd>The first two fields show the date (Modified Julian Day) and time
(seconds and fraction past UTC midnight). The next field shows the clock
address in dotted-quad notation, The final field shows the last timecode
received from the clock in decoded ASCII format, where meaningful. In
some clock drivers a good deal of additional information can be gathered
and displayed as well. See information specific to each clock for
further details.

<p><dt><code>statsdir <i>directory_path</i></code>
<dd>Indicates the full path of a directory where statistics files should
be created (see below). This keyword allows the (otherwise constant)
<code>filegen</code> filename prefix to be modified for file generation
sets, which is useful for handling statistics logs.

<p><dt><code>filegen <i>name</i> [ file <i>filename</i> ] [ type
<i>typename</i> ] [ flag <i>flagval</i> ] [ link | nolink ] [ enable |
disable ]</code>
<dd>Configures setting of generation file set <i>name</i>. Generation
file sets provide a means for handling files that are continuously
growing during the lifetime of a server. Server statistics are a typical
example for such files. Generation file sets provide access to a set of
files used to store the actual data. At any time at most one element of
the set is being written to. The type given specifies when and how data
will be directed to a new element of the set. This way, information
stored in elements of a file set that are currently unused are available
for administrational operations without the risk of disturbing the
operation of <code>xntpd</code>. (Most important: they can be removed to
free space for new data produced.)

<p><dd>Filenames of set members are built from three elements:

<dl>

<dt><code>prefix</code>
<dd>This is a constant filename path. It is not subject to modifications
via the <code>filegen</code> option. It is defined by the server,
usually specified as a compile-time constant. It may, however, be
configurable for individual file generation sets via other commands. For
example, the prefix used with <code>loopstats</code> and
<code>peerstats</code> generation can be configured using the
<code>statsdir</code> option explained above.

<p><dt><code>filename</code>
<dd>This string is directly concatenated to the prefix mentioned above
(no intervening <code>/</code> (slash)). This can be modified using the
<code>file</code> argument to the <code>filegen</code> statement. No
<code>..</code> elements are allowed in this component to prevent
filenames referring to parts outside the filesystem hierarchy denoted by
<code>prefix</code>.

<p><dt><code>suffix</code>
<dd>This part is reflects individual elements of a file set. It is
generated according to the type of a file set.

</dl>

<p><dd>A file generation set is characterized by its type. The following
types are supported:

<dl>

<dt><code>none</code>
<dd>The file set is actually a single plain file.

<p><dt><code>pid</code>
<dd>One element of file set is used per incarnation of a
<code>xntpd</code> server. This type does not perform any changes to
file set members during runtime, however it provides an easy way of
separating files belonging to different <code>xntpd</code> server
incarnations. The set member filename is built by appending a
<code>.</code> (dot) to concatenated <i>prefix</i> and <i>filename</i>
strings, and appending the decimal representation of the process ID of
the <code>xntpd</code> server process.

<p><dt><code>day</code>
<dd>One file generation set element is created per day. A day is defined
as the period between 00:00 and 24:00 UTC. The file set member suffix
consists of a <code>.</code> (dot) and a day specification in the form
<code>YYYYMMDD. YYYY</code> is a 4-digit year number (e.g., 1992).
<code>MM</code> is a two digit month number. <code>DD</code> is a two
digit day number. Thus, all information written at 10 December 1992
would end up in a file named <code><i>prefix
filename</i>.19921210</code>.

<p><dt><code>week</code>
<dd>Any file set member contains data related to a certain week of a
year. The term week is defined by computing day-of-year modulo 7.
Elements of such a file generation set are distinguished by appending
the following suffix to the file set filename base: A dot, a 4-digit
year number, the letter <code>W</code>, and a 2-digit week number. For
example, information from January, 10th 1992 would end up in a file with
suffix <code>.1992W1</code>.

<p><dt><code>month</code>
<dd>One generation file set element is generated per month. The file
name suffix consists of a dot, a 4-digit year number, and a 2-digit
month.

<p><dt><code>year</code>
<dd>One generation file element is generated per year. The filename
suffix consists of a dot and a 4 digit year number.

<p><dt><code>age</code>
<dd>This type of file generation sets changes to a new element of the
file set every 24 hours of server operation. The filename suffix
consists of a dot, the letter <code>a</code>, and an 8-digit number.
This number is taken to be the number of seconds the server is running
at the start of the corresponding 24-hour period.

<p><dd>Information is only written to a file generation by specifying
<code>enabl</code>; output is prevented by specifying
<code>disable</code>.

</dl>

<p><dd>It is convenient to be able to access the current element of a
file generation set by a fixed name. This feature is enabled by
specifying <code>link</code> and disabled using <code>nolink</code>. If
<code>link</code> is specified, a hard link from the current file set
element to a file without suffix is created. When there is already a
file with this name and the number of links of this file is one, it is
renamed appending a dot, the letter <code>C</code>, and the pid of the
<code>xntpd</code> server process. When the number of links is greater
than one, the file is unlinked. This allows the current file to be
accessed by a constant name.

</dl>

<hr><address>David L. Mills (mills@udel.edu)</address></body></html>
