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Manual Reference Pages  -  SYMUX (8)


symux - symon stream multiplexer


Legacy Formats
See Also


symux [-dltv] [-f filename]


symon(8) 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 symux for further processing.

symon(8) has been designed to inflict minimal performance and security impact on the system it monitors. symux has performance impact proportional to the amount of streams it needs to manage. Ideally symux should live on a different system and collect data from several symon(8) instances in a LAN. symux stores the incoming streams in .rrd files and distributes the information to connected listeners. Listeners can connect to symux on a tcp port and receive incoming symon(8) transmissions decoded into ascii.
.Lp symux needs no specific privileges besides being able to open it’s ports and the rrd files. It should be run as nobody.
.Lp The options:
-d Stop symux from becoming a daemon and show debug information on stdout. Use this setting to find hosts or specific statistics that do get sent, but are ignored due to configuration.
-f filename
  Read configuration from filename instead of /etc/symux.conf.
-l List rrd files found in active configuration.
-t Test configuration file and exit.
-v Show version.


symux obtains configuration data from /etc/symux.conf. The configuration file contains one mux stanza that defines on what host address and port symux should listen to for incoming monitored data. There is a source section for every host that is to be monitored. The source section defines what data to accept and where to write that data to. In the case that a source is of another address family than the mux stanza, i.e. source = ipv6 with mux = ipv4, a listen port of the sources’ family is opened using the unspecified address. Whitespace, newlines and text behind ’#’ are ignored. The format in BNF:

stmt         = mux-stmt | source-stmt
mux-stmt     = "mux" host [ port ]
host         = ip4addr | ip6addr | hostname
port         = [ "port" | "," ] portnumber
source-stmt  = "source" host "{"
               [ write-stmts ]
               [ datadir-stmt ] "}"
accept-stmts = accept-stmt [accept-stmts]
accept-stmt  = "accept" "{" resources "}"
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 | interfacename | diskname
datadir-stmt = "datadir" dirname
write-stmts  = write-stmt [write-stmts]
write-stmt   = "write" resource "in" filename

Note that
port in the mux-stmt specifies the port-number for both the udp port (incoming symon(8) traffic) and the tcp port for incoming listeners.
  is needed to distinguish between the same type of information (i.e. io ) coming from different versions of OpenBSD. If no version number is supplied, the latest will be assumed.
  will guess filenames for all accepted streams. write statements always take precendence over a datadir statement.


Here is an example symux.conf that listens to udp port 2100 on lo0, and accepts cpu, memory, pf, interfaces xl0/de0/lo0/wi0, disks wd[0-3]/cd[0-1], disk free blocks of three partition streams from a symon(8) on localhost. symux will also listen on tcp port 2100 for incoming listeners.

mux 2100
source {
    accept { cpu(0), mem, pf,
             if(xl0), if(de0),
             if(lo0), if(wi0),
             io(wd0), io(wd1), io(wd2),
             io(wd3), io(cd0), io(cd1),
             df(sd0a), df(sd0d), df(sd0e) }

datadir "/var/www/symon/rrds/localhost" }


symux offers received symon(8) data to other programs via tcp. An example of a listener session:

nexus:~/project/symon$ telnet 2100
Connected to
Escape character is ’^]’.;mem::1077662160:7630848:53850112:469417984:0:25600;cpu:0: 1077662160:0.00:0.00:0.30:0.20:99.50;io:wd0:1077662160:2074:12759: 0:30736384:131780608;;mbuf::1077658247:138:74:0:0:41:0:23:0:90:360:868352:25:0: 0:0;pf::1077658247:700930123:535398451:0:352:1107229:706391:119833 9:4:0:0:2:3:29:4109383:83291:83262:980325:0:1:6:0:0;mem::107765824 7:79155200:131956736:391430144:0:536739840;cpu:0:1077658247:0.50:0 .00:0.00:0.90:98.60;proc:httpd:1077658247:9:216:172:8:3:0.00:14999 552:0;if:lo0:1077658247:147104:147104:45868177:45868177:0:0:0:0:0: 0;if:xl0:1077658247:284267:452077:150620236:273265863:372:89478:0: 0:0:0;if:de0:1077658247:1813721:1197722:729054136:568900227:101:2: 0:0:198:0;

^] telnet> close Connection closed.

.Lp The format is symon-version : symon-host-ip : stream-name : stream-argument : timestamp : data
.Lp Data formats:
cpu Time spent in ( user, nice, system, interrupt, idle ). Total time is 100, data is offered with precision 2.
  Time spent in ( user, nice, system, interrupt, idle, iowait ). Total time is 100, data is offered with precision 2.
debug Kernel variables debug0 to debug19. ( debug0 : ... : debug19 ). Values are 32 bit unsigned integers.
df Disk free statistics ( blocks : bfree : bavail : files : ffree : synwrites : asyncwrites). Values are 64 bit unsigned integers.
load Load averages for the last 1, 5, and 15 minutes. Data is offered with precision 2 and a maximum of 655.
if Alias for if2. See below.
if1 Pre OpenBSD 4.3 interface counters ( packets_in, packets_out, bytes_in, bytes_out, multicasts_in, multicasts_out, errors_in, errors_out, collisions, drops ). Values are 32 bit unsigned integers.
if2 Interface counters ( packets_in, packets_out, bytes_in, bytes_out, multicasts_in, multicasts_out, errors_in, errors_out, collisions, drops ). Values are 64 bit unsigned integers.
io Alias for io2. See below.
io1 Pre OpenBSD 3.5 io/disk counters ( total_transfers, total_seeks, total_bytes ). Values are 64 bit unsigned integers.
io2 Io/disk counters ( total_rxfer, total_wxfer, total_seeks, total_rbytes, total_wbytes). Values are 64 bit unsigned integers.
mbuf Mbuf statistics ( totmbufs : mt_data : mt_oobdata : mt_control : mt_header : mt_ftable : mt_soname : mt_soopts : pgused : pgtotal : totmem : totpct : m_drops : m_wait : m_drain ).
mem Alias for mem2. See below.
mem1 Pre symon 2.78 memory counters ( real_active, real_total, free, swap_used, swap_total ). All values are in bytes rounded to page boundaries. Values are 32 bit unsigned integers.
mem2 Memory in ( real_active, real_total, free, swap_used, swap_total ). All values are in bytes rounded to page boundaries. Values are 64 bit unsigned integers.
pf Packet filter statistics ( bytes_v4_in : bytes_v4_out : bytes_v6_in : bytes_v6_out : packets_v4_in_pass : packets_v4_in_drop : packets_v4_out_pass : packets_v4_out_drop : packets_v6_in_pass : packets_v6_in_drop : packets_v6_out_pass : packets_v6_out_drop : states_entries : states_searches : states_inserts : states_removals : counters_match : counters_badoffset : counters_fragment : counters_short : counters_normalize : counters_memory ). Values are 64 bit unsigned integers.
pfq pf/altq queue statistics ( sent_bytes : sent_packets : drop_bytes : drop_packets ). Values are 64 bit unsigned integers.
proc Process statistics ( number : uticks : sticks : iticks : cpusec : cpupct : procsz : rsssz ).
  Single sensor measurement offered with 7.6 precision. Value depends on sensor type.
smart SMART attributes ( read_error_rate: reallocated_sectors: spin_retries: air_flow_temp: temperature: reallocations: current_pending: uncorrectables: soft_read_error_rate: g_sense_error_rate: temperature2: free_fall_protection ). Values depend on drive model and may change between models.
  Average pwr sensor value offered with 7.6 precision. Value is a moving average and will depend on the number of measurements seen in a particular symon interval.


  Causes symux to read /etc/symux.conf or the file specified by the -f flag. symux will keep the old configuration if errors occured during parsing of the configuration file.


  Contains the program id of the symux daemon.
  symux system wide configuration file.


symux supports symon(8) clients that send
pre OpenBSD 3.5 disk statistics.
  These streams should be identified as io1(<disk>) instead of io(<disk>) in /etc/symux.conf. Also note that symon(8) measures io1 or io2 depending on whether it was compiled on a host that supports version 1 or 2. The rrd datastructures of these streams differ and there is no easy way to change an io1 rrd into an io2 rrd.
pre symon 2.78 mem/if statistics.
  These streams should be identified as if1(<interface>) and mem1() in /etc/symux.conf. symon versions 2.78 and up will always report if2 and mem2 statistics. The rrd files for the old and new probes are identical and need not be changed.

symux will output what version of information it is offered by symon(8)s on the network when started with the -d flag.


symux writes incoming data to rrd files "in process". An rrdupdate on a somewhat stale rrdfile -- with the last data from quite some time in the past -- is a very expensive operation. This can cause symux to lockup while rrdupdate is updating the rrd file. symux will be unresponsive during this process.


Willem Dijkstra <>.  Daniel  Hartmeier helped to port to big-endian architectures.  Matthew  Gream helped to port symon to other BSD platforms.

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.


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