Monitoring Options
Monitoring Support
ntpd includes a comprehensive monitoring facility suitable for
continuous, long term recording of server and client timekeeping
performance. See the statistics 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
cron jobs, the datacan be automatically summarized and archived
for retrospective analysis.
Monitoring Commands
- statistics name [...]
- Enables writing of statistics records. Currently, four kinds of
namestatistics are supported.
- loopstats
- 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 loopstats:
- 50935 75440.031 0.000006019 13.778190 0.000351733 0.013380
6
- The first two fields show the date (Modified Julian Day) and time
(seconds and fraction past UTC midnight). The next five fields show time
offset (seconds), frequency offset (parts per million - PPM), RMS jitter
(seconds), Allan deviation (PPM) and clock discipline time
constant.
- peerstats
- 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
peerstats:
- 48773 10847.650 127.127.4.1 9714 -0.001605 0.00000
0.00142
- 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 RMS jitter, all in seconds.
- clockstats
- Enables recording of clock driver statistics information. Each
update received from a clock driver appends a line of the following form
to the file generation set named clockstats:
- 49213 525.624 127.127.4.1 93 226 00:08:29.606 D
- 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.
- rawstats
- Enables recording of raw-timestamp statistics information. This
includes statistics records of all peers of a NTP server and of special
signals, where present and configured. Each NTP message received from a
peer or clock driver appends a line of the following form to the file
generation set named rawstats:
- 50928 2132.543 128.4.1.1 128.4.1.20 3102453281.584327000
3102453281.58622800031 02453332.540806000 3102453332.541458000
- The first two fields show the date (Modified Julian Day) and time
(seconds and fraction past UTC midnight). The next two fields show the
remote peer or clock address followed by the local address in
dotted-quad notation, The final four fields show the originate, receive,
transmit and final NTP timestamps in order. The timestamp values are as
received and before processing by the various data smoothing and
mitigation algorithms.
- statsdir directory_path
- Indicates the full path of a directory where statistics files should
be created (see below). This keyword allows the (otherwise constant)
filegen filename prefix to be modified for file generation
sets, which is useful for handling statistics logs.
- filegen name [file filename] [type
typename] [link | nolink] [enable | disable]
- Configures setting of generation file set name. 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 ntpd. (Most important: they can be removed to free
space for new data produced.)
- Note that this command can be sent from the ntpdc program
running at a remote location.
- name
- This is the type of the statistics records, as shown in the
statististics command.
- file filename
- This is the file name for the statistics records. Filenames of set
members are built from three concatenated elements
prefix, filename and
suffix:
- prefix
- This is a constant filename path. It is not subject to modifications
via the filegen 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 loopstats and peerstats generation
can be configured using the statsdir option explained
above.
- filename
- This string is directly concatenated to the prefix mentioned above
(no intervening / (slash)). This can be modified using the
file argument to the filegen statement. No ..
elements are allowed in this component to prevent filenames referring to
parts outside the filesystem hierarchy denoted by prefix.
- suffix
- This part is reflects individual elements of a file set. It is
generated according to the type of a file set.
- type typename
- A file generation set is characterized by its type. The following
types are supported:
- none
- The file set is actually a single plain file.
- pid
- One element of file set is used per incarnation of a ntpd
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 ntpd server incarnations. The set member
filename is built by appending a . (dot) to concatenated
prefix and filename strings, and appending the decimal
representation of the process ID of the ntpd server
process.
- day
- 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 . (dot) and a day specification in the form
YYYYMMdd. YYYY is a 4-digit year number (e.g., 1992).
MM is a two digit month number. dd is a two digit day
number. Thus, all information written at 10 December 1992 would end up
in a file named prefix filename.19921210.
- week
- 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 W, and a 2-digit week number. For
example, information from January, 10th 1992 would end up in a file with
suffix .1992W1.
- month
- 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.
- year
- One generation file element is generated per year. The filename
suffix consists of a dot and a 4 digit year number.
- age
- 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 a, 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. Information is only written
to a file generation by specifying enable; output is prevented
by specifying disable.
- link | nolink
- 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
link and disabled using nolink. If link 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 C, and the pid of the ntpd 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.
- enable | disable
- Enables or disables the recording function.
Home David L. Mills <mills@udel.edu>