symon/symon/symon/symon.8

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.Dd October 20, 2010
.Dt SYMON 8
.Os
.Sh NAME
.Nm symon
.Nd system monitor
.Sh SYNOPSIS
.Nm
.Op Fl dtuv
.Op Fl f Ar filename
.Pp
.Sh DESCRIPTION
.Nm
is a lightweight system monitor that measures cpu, load, filesystem, interface, disk,
memory, pf, pf queues, mbuf, proc and sensor statistics every 5 seconds. This
information is then spooled to
.Xr symux 8
for further processing.
.Pp
.Nm
has been designed to inflict minimal performance and security impact on
the system it monitors.
.Xr symux 8
has performance impact proportional to the amount of streams it needs to
manage. Ideally
.Xr symux
should live on a different system and collect data from several
.Nm
instances in a LAN.
.Lp
By default,
.Nm
will drop privileges and chroot(2) to home of the symon user.  This behaviour
is not strictly needed for the cpu, mem, mbuf, disk debug and interface probes
as these will work even when
.Nm
is started as
.Ar "nobody".
.Lp
The options:
.Bl -tag -width Ds
.It Fl d
Stop
.Nm
from becoming a daemon and show debug information on stdout.
.It Fl f Ar filename
Read configuration from
.Ar filename
instead of
.Pa /etc/symon.conf .
.It Fl t
Test configuration file and exit.
.It Fl u
By default
.Nm
will chroot(2) into
.Pa _symon
user home directory. The
.Pa -u
disables this behaviour.
.It Fl v
Show version information.
.El
.Sh CONFIGURATION
.Nm
obtains configuration data from
.Pa /etc/symon.conf .
The configuration file contains monitor stanzas that define what
resources should be monitored and to which
.Xr symux 8
the information should be streamed to.
.Pp
Multiple monitor statements are allowed. Whitespace, newlines and text
behind '#' are ignored. The format in BNF:
.Pp
.Bd -literal -offset indent -compact
monitor-rule = "monitor" "{" resources "}" [every]
               "stream" ["from" host] ["to"] host [ port ]
resources    = resource [ version ] ["(" argument ")"]
               [ ","|" " resources ]
resource     = "cpu" | "cpuiow" | "debug" | "df" | "flukso" |
               "if" | "io" | "load" | "mbuf" | "mem" | "pf" |
               "pfq" | "proc" | "sensor" | "smart"
version      = number
argument     = number | name
every        = "every" time
time         = "second" | number "seconds"
host         = ip4addr | ip6addr | hostname
port         = [ "port" | "," ] portnumber
.Ed
.Pp
Note that symux(8) data files default to receiving data every 5
seconds. Adjusting the monitoring interval will also require adjusting the
associated symux(8) datafile(s).
.Pp
The pf probe will return data that is collected for the
.Pa loginterface
set in /etc/pf.conf(5).
.Pp
The Linux io, df, and smart probes support device names via id, label, path and uuid.
.Pp
The OpenBSD io probe supports device uuids.
.Pp
.Sh EXAMPLE
Here is an example OpenBSD
.Ar symon.conf
that monitors cpu, memory, pf, interfaces xl0/de0/lo0/wi0, disks
wd[0-3]/cd[0-1], debug variables debug0 to debug19 and streams that
information to localhost on port 2100.
.Pp
.Bd -literal -offset indent -compact
monitor { cpu(0),  mem, pf, if(xl0), if(de0),
	  if(lo0), if(wi0), io(wd0), io(wd1),
	  io(wd2), io(wd3), io(cd0), io(cd1),
	  io(ccd0), df(sd0a), df(sd0d), df(sd0e),
	  debug, proc(httpd) } stream to 127.0.0.1 2100
.Ed
.Sh EXAMPLE
Here is an example Linux
.Ar symon.conf
that monitors cpu including iowait, memory, load, interface eth0, io and df for
a set of disks every 5 seconds. Smart data is to be collected every 60 seconds.
Disks in the smart and io statements are identified using ids, filesystem
volumes in df using labels.
.Bd -literal -offset indent -compact
monitor { smart(ata-Hitachi_HDS722020ALA330_JK1130ABABABAB),
          smart(ata-Hitachi_HDS722020ALA330_JK1130ACACACAC),
        } every 60 seconds stream to 192.168.0.2 port 2100

monitor { cpuiow(0), cpuiow(1), mem, if(eth0),
          io(ata-Hitachi_HDS722020ALA330_JK1130ABABABAB),
          io(ata-Hitachi_HDS722020ALA330_JK1130ACACACAC),
          df(data_1),
          df(data_2),
          df(data_3),
          df(home),
          df(var),
          load
        } stream to 192.168.0.2 port 2100
.Ed
.Sh SIGNALS
.Bl -tag -width Ds
.It SIGHUP
Causes
.Nm
to read
.Pa /etc/symon.conf .
.Nm
will keep the old configuration if errors occured during parsing of the
configuration file. Note that the chroot(2) may cause resources to become
unattainable, most notably the configuration file itself.
.El
.Sh FILES
.Bl -tag -width Ds
.It Pa /var/run/symon.pid
Contains the program id of the
.Nm
daemon.
.It Pa /etc/symon.conf
.Nm
system wide configuration file.
.El
.Sh BUGS
Every monitored resource mentioned
.Pa /etc/symon.conf
gets queried. Mentioning, for example, cpu(0) twice for different muxes will
result in two distinct cpu(0) measurement actions.
.Pp
The proc module is too simple: memory shared between two instances of the same
process is simply counted twice.
.Pp
.Nm
does not check whether all resources mentioned in
.Pa /etc/symon.conf
exist.
.Pp
.Sh AUTHOR
Willem Dijkstra <wpd@xs4all.nl>. \%Daniel \%Hartmeier helped to port to big-endian
architectures. \%Matthew \%Gream helped to port symon to other BSD platforms.
.Pp
Port contributors: \%Marc \%Balmer, \%Tito \%Dal \%Canton, \%Matthew
\%Gream, \%Daniel \%Hartmeier, \%Lars \%Kotthoff, \%Constantine
A. \%Murenin, J. \%Martin \%Petersen, \%Fredrik \%Soderblom, \%Harm
\%Schotanus and \%Martin van der \%Werff.
.Sh SEE ALSO
.Xr symux 8