1 collectd - System information collection daemon
2 =================================================
8 collectd is a small daemon which collects system information periodically
9 and provides mechanisms to store and monitor the values in a variety of
16 * collectd is able to collect the following data:
19 Apache server utilization: Number of bytes transferred, number of
20 requests handled and detailed scoreboard statistics
23 APC UPS Daemon: UPS charge, load, input/output/battery voltage, etc.
26 Sensors in Macs running Mac OS X / Darwin: Temperature, fan speed and
30 Various sensors in the Aquaero 5 water cooling board made by Aquacomputer.
33 Statistics about Ascent, a free server for the game `World of Warcraft'.
36 Reads absolute barometric pressure, air pressure reduced to sea level and
37 temperature. Supported sensors are MPL115A2 and MPL3115 from Freescale
38 and BMP085 from Bosch.
41 Batterycharge, -current and voltage of ACPI and PMU based laptop
45 Name server and resolver statistics from the `statistics-channel'
46 interface of BIND 9.5, 9,6 and later.
49 Statistics from the Ceph distributed storage system.
52 CPU accounting information for process groups under Linux.
55 Number of nf_conntrack entries.
58 Number of context switches done by the operating system.
61 CPU utilization: Time spent in the system, user, nice, idle, and related
65 CPU frequency (For laptops with speed step or a similar technology)
68 Parse statistics from websites using regular expressions.
71 Retrieves JSON data via cURL and parses it according to user
75 Retrieves XML data via cURL and parses it according to user
79 Executes SQL statements on various databases and interprets the returned
83 Mountpoint usage (Basically the values `df(1)' delivers)
86 Disk utilization: Sectors read/written, number of read/write actions,
87 average time an IO-operation took to complete.
90 DNS traffic: Query types, response codes, opcodes and traffic/octets
94 Collect individual drbd resource statistics.
97 Email statistics: Count, traffic, spam scores and checks.
98 See collectd-email(5).
101 Amount of entropy available to the system.
104 Network interface card statistics.
107 Values gathered by a custom program or script.
108 See collectd-exec(5).
111 File handles statistics.
114 Count the number of files in directories.
117 Linux file-system based caching framework statistics.
120 Receive multicast traffic from Ganglia instances.
123 Monitor gps related data through gpsd.
126 Hard disk temperatures using hddtempd.
129 Interface traffic: Number of octets, packets and errors for each
133 IPC counters: semaphores used, number of allocated segments in shared
137 IPMI (Intelligent Platform Management Interface) sensors information.
140 Iptables' counters: Number of bytes that were matched by a certain
144 IPVS connection statistics (number of connections, octets and packets
145 for each service and destination).
146 See http://www.linuxvirtualserver.org/software/index.html.
149 IRQ counters: Frequency in which certain interrupts occur.
152 Integrates a `Java Virtual Machine' (JVM) to execute plugins in Java
153 bytecode. See “Configuring with libjvm” below.
156 System load average over the last 1, 5 and 15 minutes.
159 Detailed CPU statistics of the “Logical Partitions” virtualization
160 technique built into IBM's POWER processors.
163 Size of “Logical Volumes” (LV) and “Volume Groups” (VG) of Linux'
164 “Logical Volume Manager” (LVM).
167 Queries very detailed usage statistics from wireless LAN adapters and
168 interfaces that use the Atheros chipset and the MadWifi driver.
171 Motherboard sensors: temperature, fan speed and voltage information,
175 Linux software-RAID device information (number of active, failed, spare
179 Query and parse data from a memcache daemon (memcached).
182 Statistics of the memcached distributed caching system.
183 <http://www.danga.com/memcached/>
186 Memory utilization: Memory occupied by running processes, page cache,
187 buffer cache and free.
190 Collects CPU usage, memory usage, temperatures and power consumption from
191 Intel Many Integrated Core (MIC) CPUs.
194 Reads values from Modbus/TCP enabled devices. Supports reading values
195 from multiple "slaves" so gateway devices can be used.
198 Publishes and subscribes to MQTT topics.
201 Information provided by serial multimeters, such as the `Metex
205 MySQL server statistics: Commands issued, handlers triggered, thread
206 usage, query cache utilization and traffic/octets sent and received.
209 Plugin to query performance values from a NetApp storage system using the
210 “Manage ONTAP” SDK provided by NetApp.
213 Very detailed Linux network interface and routing statistics. You can get
214 (detailed) information on interfaces, qdiscs, classes, and, if you can
215 make use of it, filters.
218 Receive values that were collected by other hosts. Large setups will
219 want to collect the data on one dedicated machine, and this is the
220 plugin of choice for that.
223 NFS Procedures: Which NFS command were called how often. Only NFSv2 and
227 Collects statistics from `nginx' (speak: engine X), a HTTP and mail
231 NTP daemon statistics: Local clock drift, offset to peers, etc.
234 Information about Non-Uniform Memory Access (NUMA).
237 Network UPS tools: UPS current, voltage, power, charge, utilisation,
238 temperature, etc. See upsd(8).
241 Queries routing information from the “Optimized Link State Routing”
244 - onewire (EXPERIMENTAL!)
245 Read onewire sensors using the owcapu library of the owfs project.
246 Please read in collectd.conf(5) why this plugin is experimental.
249 Read monitoring information from OpenLDAP's cn=Monitor subtree.
252 RX and TX of each client in openvpn-status.log (status-version 2).
253 <http://openvpn.net/index.php/documentation/howto.html>
256 Query data from an Oracle database.
259 The perl plugin implements a Perl-interpreter into collectd. You can
260 write your own plugins in Perl and return arbitrary values using this
261 API. See collectd-perl(5).
264 Query statistics from BSD's packet filter "pf".
267 Receive and dispatch timing values from Pinba, a profiling extension for
271 Network latency: Time to reach the default gateway or another given
275 PostgreSQL database statistics: active server connections, transaction
276 numbers, block IO, table row manipulations.
279 PowerDNS name server statistics.
282 Process counts: Number of running, sleeping, zombie, ... processes.
285 Counts various aspects of network protocols such as IP, TCP, UDP, etc.
288 The python plugin implements a Python interpreter into collectd. This
289 makes it possible to write plugins in Python which are executed by
290 collectd without the need to start a heavy interpreter every interval.
291 See collectd-python(5) for details.
294 The redis plugin gathers information from a Redis server, including:
295 uptime, used memory, total connections etc.
298 Query interface and wireless registration statistics from RouterOS.
301 RRDtool caching daemon (RRDcacheD) statistics.
304 System sensors, accessed using lm_sensors: Voltages, temperatures and
308 RX and TX of serial interfaces. Linux only; needs root privileges.
311 Uses libsigrok as a backend, allowing any sigrok-supported device
312 to have its measurements fed to collectd. This includes multimeters,
313 sound level meters, thermometers, and much more.
316 Collect SMART statistics, notably load cycle count, temperature
320 Read values from SNMP (Simple Network Management Protocol) enabled
321 network devices such as switches, routers, thermometers, rack monitoring
322 servers, etc. See collectd-snmp(5).
325 Acts as a StatsD server, reading values sent over the network from StatsD
326 clients and calculating rates and other aggregates out of these values.
329 Pages swapped out onto hard disk or whatever is called `swap' by the OS..
332 Parse table-like structured files.
335 Follows (tails) log files, parses them by lines and submits matched
339 Follows (tails) files in CSV format, parses each line and submits
343 Bytes and operations read and written on tape devices. Solaris only.
346 Number of TCP connections to specific local and remote ports.
349 TeamSpeak2 server statistics.
352 Plugin to read values from `The Energy Detective' (TED).
355 Linux ACPI thermal zone information.
358 Reads the number of records and file size from a running Tokyo Tyrant
362 Reads CPU frequency and C-state residency on modern Intel
363 turbo-capable processors.
366 System uptime statistics.
369 Users currently logged in.
372 Various statistics from Varnish, an HTTP accelerator.
375 CPU, memory, disk and network I/O statistics from virtual machines.
378 Virtual memory statistics, e. g. the number of page-ins/-outs or the
379 number of pagefaults.
382 System resources used by Linux VServers.
383 See <http://linux-vserver.org/>.
386 Link quality of wireless cards. Linux only.
389 Bitrate and frequency of music played with XMMS.
392 Statistics for ZFS' “Adaptive Replacement Cache” (ARC).
395 Measures the percentage of cpu load per container (zone) under Solaris 10
399 Read data from Zookeeper's MNTR command.
401 * Output can be written or sent to various destinations by the following
405 Sends JSON-encoded data to an Advanced Message Queuing Protocol (AMQP)
406 server, such as RabbitMQ.
409 Write to comma separated values (CSV) files. This needs lots of
410 diskspace but is extremely portable and can be analysed with almost
411 every program that can analyse anything. Even Microsoft's Excel..
414 Send the data to a remote host to save the data somehow. This is useful
415 for large setups where the data should be saved by a dedicated machine.
418 Of course the values are propagated to plugins written in Perl, too, so
419 you can easily do weird stuff with the plugins we didn't dare think of
420 ;) See collectd-perl(5).
423 It's possible to implement write plugins in Python using the python
424 plugin. See collectd-python(5) for details.
427 Output to round-robin-database (RRD) files using the RRDtool caching
428 daemon (RRDcacheD) - see rrdcached(1). That daemon provides a general
429 implementation of the caching done by the `rrdtool' plugin.
432 Output to round-robin-database (RRD) files using librrd. See rrdtool(1).
433 This is likely the most popular destination for such values. Since
434 updates to RRD-files are somewhat expensive this plugin can cache
435 updates to the files and write a bunch of updates at once, which lessens
439 One can query the values from the unixsock plugin whenever they're
440 needed. Please read collectd-unixsock(5) for a description on how that's
444 Sends data to Carbon, the storage layer of Graphite using TCP or UDP. It
445 can be configured to avoid logging send errors (especially useful when
449 Sends the values collected by collectd to a web-server using HTTP POST
450 requests. The transmitted data is either in a form understood by the
451 Exec plugin or formatted in JSON.
454 Sends data to Apache Kafka, a distributed queue.
457 Writes data to the log
460 Sends data to MongoDB, a NoSQL database.
463 Sends the values to a Redis key-value database server.
466 Sends data to Riemann, a stream processing and monitoring system.
469 Sends data to Sensu, a stream processing and monitoring system, via the
470 Sensu client local TCP socket.
473 Sends data OpenTSDB, a scalable no master, no shared state time series
476 * Logging is, as everything in collectd, provided by plugins. The following
477 plugins keep us informed about what's going on:
480 Writes log messages to a file or STDOUT/STDERR.
483 Log messages are propagated to plugins written in Perl as well.
484 See collectd-perl(5).
487 It's possible to implement log plugins in Python using the python plugin.
488 See collectd-python(5) for details.
491 Logs to the standard UNIX logging mechanism, syslog.
494 Writes log messages formatted as logstash JSON events.
496 * Notifications can be handled by the following plugins:
499 Send a desktop notification to a notification daemon, as defined in
500 the Desktop Notification Specification. To actually display the
501 notifications, notification-daemon is required.
502 See http://www.galago-project.org/specs/notification/.
505 Send an E-mail with the notification message to the configured
509 Execute a program or script to handle the notification.
510 See collectd-exec(5).
513 Writes the notification message to a file or STDOUT/STDERR.
516 Send the notification to a remote host to handle it somehow.
519 Notifications are propagated to plugins written in Perl as well.
520 See collectd-perl(5).
523 It's possible to implement notification plugins in Python using the
524 python plugin. See collectd-python(5) for details.
526 * Value processing can be controlled using the "filter chain" infrastructure
527 and "matches" and "targets". The following plugins are available:
529 - match_empty_counter
530 Match counter values which are currently zero.
533 Match values using a hash function of the hostname.
536 Match values by their identifier based on regular expressions.
539 Match values with an invalid timestamp.
542 Select values by their data sources' values.
544 - target_notification
545 Create and dispatch a notification.
548 Replace parts of an identifier using regular expressions.
551 Scale (multiply) values by an arbitrary value.
554 Set (overwrite) entire parts of an identifier.
556 * Miscellaneous plugins:
559 Selects multiple value lists based on patterns or regular expressions
560 and creates new aggregated values lists from those.
563 Checks values against configured thresholds and creates notifications if
564 values are out of bounds. See collectd-threshold(5) for details.
567 Sets the hostname to a unique identifier. This is meant for setups
568 where each client may migrate to another physical host, possibly going
569 through one or more name changes in the process.
571 * Performance: Since collectd is running as a daemon it doesn't spend much
572 time starting up again and again. With the exception of the exec plugin no
573 processes are forked. Caching in output plugins, such as the rrdtool and
574 network plugins, makes sure your resources are used efficiently. Also,
575 since collectd is programmed multithreaded it benefits from hyper-threading
576 and multicore processors and makes sure that the daemon isn't idle if only
577 one plugin waits for an IO-operation to complete.
579 * Once set up, hardly any maintenance is necessary. Setup is kept as easy
580 as possible and the default values should be okay for most users.
586 * collectd's configuration file can be found at `sysconfdir'/collectd.conf.
587 Run `collectd -h' for a list of built-in defaults. See `collectd.conf(5)'
588 for a list of options and a syntax description.
590 * When the `csv' or `rrdtool' plugins are loaded they'll write the values to
591 files. The usual place for these files is beneath `/var/lib/collectd'.
593 * When using some of the plugins, collectd needs to run as user root, since
594 only root can do certain things, such as craft ICMP packages needed to ping
595 other hosts. collectd should NOT be installed setuid root since it can be
596 used to overwrite valuable files!
598 * Sample scripts to generate graphs reside in `contrib/' in the source
599 package or somewhere near `/usr/share/doc/collectd' in most distributions.
600 Please be aware that those script are meant as a starting point for your
601 own experiments.. Some of them require the `RRDs' Perl module.
602 (`librrds-perl' on Debian) If you have written a more sophisticated
603 solution please share it with us.
605 * The RRAs of the automatically created RRD files depend on the `step'
606 and `heartbeat' settings given. If change these settings you may need to
607 re-create the files, losing all data. Please be aware of that when changing
608 the values and read the rrdtool(1) manpage thoroughly.
611 collectd and chkrootkit
612 -----------------------
614 If you are using the `dns' plugin chkrootkit(1) will report collectd as a
615 packet sniffer ("<iface>: PACKET SNIFFER(/usr/sbin/collectd[<pid>])"). The
616 plugin captures all UDP packets on port 53 to analyze the DNS traffic. In
617 this case, collectd is a legitimate sniffer and the report should be
618 considered to be a false positive. However, you might want to check that
619 this really is collectd and not some other, illegitimate sniffer.
625 To compile collectd from source you will need:
627 * Usual suspects: C compiler, linker, preprocessor, make, ...
629 * A POSIX-threads (pthread) implementation.
630 Since gathering some statistics is slow (network connections, slow devices,
631 etc) collectd is parallelized. The POSIX threads interface is being
632 used and should be found in various implementations for hopefully all
635 * aerotools-ng (optional)
636 Used by the `aquaero' plugin. Currently, the `libaquaero5' library, which
637 is used by the `aerotools-ng' toolkit, is not compiled as a shared object
638 nor does it feature an installation routine. Therefore, you need to point
639 collectd's configure script at the source directory of the `aerotools-ng'
641 <https://github.com/lynix/aerotools-ng>
643 * CoreFoundation.framework and IOKit.framework (optional)
644 For compiling on Darwin in general and the `apple_sensors' plugin in
646 <http://developer.apple.com/corefoundation/>
648 * libatasmart (optional)
649 Used by the `smart' plugin.
650 <http://git.0pointer.de/?p=libatasmart.git>
653 The `turbostat' plugin can optionally build Linux Capabilities support,
654 which avoids full privileges requirement (aka. running as root) to read
656 <http://sites.google.com/site/fullycapable/>
658 * libclntsh (optional)
659 Used by the `oracle' plugin.
661 * libhiredis (optional)
662 Used by the redis plugin. Please note that you require a 0.10.0 version
663 or higher. <https://github.com/redis/hiredis>
666 If you want to use the `apache', `ascent', `bind', `curl', `curl_json',
667 `curl_xml', `nginx', or `write_http' plugin.
668 <http://curl.haxx.se/>
671 Used by the `dbi' plugin to connect to various databases.
672 <http://libdbi.sourceforge.net/>
674 * libesmtp (optional)
675 For the `notify_email' plugin.
676 <http://www.stafford.uklinux.net/libesmtp/>
678 * libganglia (optional)
679 Used by the `gmond' plugin to process data received from Ganglia.
680 <http://ganglia.info/>
682 * libgcrypt (optional)
683 Used by the `network' plugin for encryption and authentication.
684 <http://www.gnupg.org/>
687 Used by the `gps' plugin.
688 <http://developer.berlios.de/projects/gpsd/>
691 If present, the `uuid' plugin will check for UUID from HAL.
692 <http://hal.freedesktop.org/>
694 * libi2c-dev (optional)
695 Used for the plugin `barometer', provides just the i2c-dev.h header file
696 for user space i2c development.
699 For querying iptables counters.
700 <http://netfilter.org/>
703 Library that encapsulates the `Java Virtual Machine' (JVM). This library is
704 used by the `java' plugin to execute Java bytecode. See “Configuring with
706 <http://openjdk.java.net/> (and others)
709 Used by the `openldap' plugin.
710 <http://www.openldap.org/>
713 Used by the `lvm' plugin.
714 <ftp://sources.redhat.com/pub/lvm2/>
716 * libmemcached (optional)
717 Used by the `memcachec' plugin to connect to a memcache daemon.
718 <http://tangent.org/552/libmemcached.html>
721 Used by the `netlink' plugin.
722 <http://www.netfilter.org/projects/libmnl/>
724 * libmodbus (optional)
725 Used by the `modbus' plugin to communicate with Modbus/TCP devices. The
726 `modbus' plugin works with version 2.0.3 of the library – due to frequent
727 API changes other versions may or may not compile cleanly.
728 <http://www.libmodbus.org/>
730 * libmysqlclient (optional)
731 Unsurprisingly used by the `mysql' plugin.
732 <http://dev.mysql.com/>
734 * libnetapp (optional)
735 Required for the `netapp' plugin.
736 This library is part of the “Manage ONTAP SDK” published by NetApp.
738 * libnetsnmp (optional)
739 For the `snmp' plugin.
740 <http://www.net-snmp.org/>
742 * libnotify (optional)
743 For the `notify_desktop' plugin.
744 <http://www.galago-project.org/>
746 * libopenipmi (optional)
747 Used by the `ipmi' plugin to prove IPMI devices.
748 <http://openipmi.sourceforge.net/>
750 * liboping (optional)
751 Used by the `ping' plugin to send and receive ICMP packets.
752 <http://octo.it/liboping/>
754 * libowcapi (optional)
755 Used by the `onewire' plugin to read values from onewire sensors (or the
757 <http://www.owfs.org/>
760 Used to capture packets by the `dns' plugin.
761 <http://www.tcpdump.org/>
763 * libperfstat (optional)
764 Used by various plugins to gather statistics under AIX.
767 Obviously used by the `perl' plugin. The library has to be compiled with
768 ithread support (introduced in Perl 5.6.0).
769 <http://www.perl.org/>
772 The PostgreSQL C client library used by the `postgresql' plugin.
773 <http://www.postgresql.org/>
775 * libprotobuf-c, protoc-c (optional)
776 Used by the `pinba' plugin to generate a parser for the network packets
777 sent by the Pinba PHP extension, and by the `write_riemann' plugin to
778 generate events to be sent to a Riemann server.
779 <http://code.google.com/p/protobuf-c/>
781 * libpython (optional)
782 Used by the `python' plugin. Currently, Python 2.3 and later and Python 3
784 <http://www.python.org/>
786 * librabbitmq (optional; also called “rabbitmq-c”)
787 Used by the `amqp' plugin for AMQP connections, for example to RabbitMQ.
788 <http://hg.rabbitmq.com/rabbitmq-c/>
790 * librdkafka (optional; also called “rdkafka”)
791 Used by the `write_kafka' plugin for producing messages and sending them
793 <https://github.com/edenhill/librdkafka>
795 * librouteros (optional)
796 Used by the `routeros' plugin to connect to a device running `RouterOS'.
797 <http://octo.it/librouteros/>
800 Used by the `rrdtool' and `rrdcached' plugins. The latter requires RRDtool
801 client support which was added after version 1.3 of RRDtool. Versions 1.0,
802 1.2 and 1.3 are known to work with the `rrdtool' plugin.
803 <http://oss.oetiker.ch/rrdtool/>
805 * librt, libsocket, libkstat, libdevinfo (optional)
806 Various standard Solaris libraries which provide system functions.
807 <http://developers.sun.com/solaris/>
809 * libsensors (optional)
810 To read from `lm_sensors', see the `sensors' plugin.
811 <http://www.lm-sensors.org/>
813 * libsigrok (optional)
814 Used by the `sigrok' plugin. In addition, libsigrok depends on glib,
815 libzip, and optionally (depending on which drivers are enabled) on
816 libusb, libftdi and libudev.
818 * libstatgrab (optional)
819 Used by various plugins to collect statistics on systems other than Linux
821 <http://www.i-scream.org/libstatgrab/>
823 * libtokyotyrant (optional)
824 Used by the `tokyotyrant' plugin.
825 <http://1978th.net/tokyotyrant/>
827 * libupsclient/nut (optional)
828 For the `nut' plugin which queries nut's `upsd'.
829 <http://networkupstools.org/>
832 Collect statistics from virtual machines.
833 <http://libvirt.org/>
836 Parse XML data. This is needed for the `ascent', `bind', `curl_xml' and
838 <http://xmlsoft.org/>
841 <http://www.xmms.org/>
844 Parse JSON data. This is needed for the `ceph', `curl_json' and
845 `log_logstash' plugins.
846 <http://github.com/lloyd/yajl>
848 * libvarnish (optional)
849 Fetches statistics from a Varnish instance. This is needed for the
851 <http://varnish-cache.org>
853 Configuring / Compiling / Installing
854 ------------------------------------
856 To configure, build and install collectd with the default settings, run
857 `./configure && make && make install'. For detailed, generic instructions
858 see INSTALL. For a complete list of configure options and their description,
859 run `./configure --help'.
861 By default, the configure script will check for all build dependencies and
862 disable all plugins whose requirements cannot be fulfilled (any other plugin
863 will be enabled). To enable a plugin, install missing dependencies (see
864 section `Prerequisites' above) and rerun `configure'. If you specify the
865 `--enable-<plugin>' configure option, the script will fail if the depen-
866 dencies for the specified plugin are not met. In that case you can force the
867 plugin to be built using the `--enable-<plugin>=force' configure option.
868 This will most likely fail though unless you're working in a very unusual
869 setup and you really know what you're doing. If you specify the
870 `--disable-<plugin>' configure option, the plugin will not be built. If you
871 specify the `--enable-all-plugins' or `--disable-all-plugins' configure
872 options, all plugins will be enabled or disabled respectively by default.
873 Explicitly enabling or disabling a plugin overwrites the default for the
874 specified plugin. These options are meant for package maintainers and should
875 not be used in everyday situations.
877 By default, collectd will be installed into `/opt/collectd'. You can adjust
878 this setting by specifying the `--prefix' configure option - see INSTALL for
879 details. If you pass DESTDIR=<path> to `make install', <path> will be
880 prefixed to all installation directories. This might be useful when creating
881 packages for collectd.
883 Configuring with libjvm
884 -----------------------
886 To determine the location of the required files of a Java installation is not
887 an easy task, because the locations vary with your kernel (Linux, SunOS, …)
888 and with your architecture (x86, SPARC, …) and there is no ‘java-config’
889 script we could use. Configuration of the JVM library is therefore a bit
892 The easiest way to use the `--with-java=$JAVA_HOME' option, where
893 `$JAVA_HOME' is usually something like:
894 /usr/lib/jvm/java-1.5.0-sun-1.5.0.14
896 The configure script will then use find(1) to look for the following files:
902 If found, appropriate CPP-flags and LD-flags are set and the following
903 library checks succeed.
905 If this doesn't work for you, you have the possibility to specify CPP-flags,
906 C-flags and LD-flags for the ‘Java’ plugin by hand, using the following three
907 (environment) variables:
913 For example (shortened for demonstration purposes):
915 ./configure JAVA_CPPFLAGS="-I$JAVA_HOME/include -I$JAVA_HOME/include/linux"
917 Adding "-ljvm" to the JAVA_LDFLAGS is done automatically, you don't have to
920 Generating the configure script
921 -------------------------------
923 Collectd ships with a `build.sh' script to generate the `configure'
924 script shipped with releases.
926 To generate the `configure` script, you'll need the following dependencies:
935 The `build.sh' script takes no arguments.
940 To compile correctly collectd needs to be able to initialize static
941 variables to NAN (Not A Number). Some C libraries, especially the GNU
942 libc, have a problem with that.
944 Luckily, with GCC it's possible to work around that problem: One can define
945 NAN as being (0.0 / 0.0) and `isnan' as `f != f'. However, to test this
946 ``implementation'' the configure script needs to compile and run a short
947 test program. Obviously running a test program when doing a cross-
948 compilation is, well, challenging.
950 If you run into this problem, you can use the `--with-nan-emulation'
951 configure option to force the use of this implementation. We can't promise
952 that the compiled binary actually behaves as it should, but since NANs
953 are likely never passed to the libm you have a good chance to be lucky.
955 Likewise, collectd needs to know the layout of doubles in memory, in order
956 to craft uniform network packets over different architectures. For this, it
957 needs to know how to convert doubles into the memory layout used by x86. The
958 configure script tries to figure this out by compiling and running a few
959 small test programs. This is of course not possible when cross-compiling.
960 You can use the `--with-fp-layout' option to tell the configure script which
961 conversion method to assume. Valid arguments are:
963 * `nothing' (12345678 -> 12345678)
964 * `endianflip' (12345678 -> 87654321)
965 * `intswap' (12345678 -> 56781234)
971 For questions, bug reports, development information and basically all other
972 concerns please send an email to collectd's mailing list at
973 <list at collectd.org>.
975 For live discussion and more personal contact visit us in IRC, we're in
976 channel #collectd on freenode.
982 Florian octo Forster <octo at collectd.org>,
983 Sebastian tokkee Harl <sh at tokkee.org>,
984 and many contributors (see `AUTHORS').
986 Please send bug reports and patches to the mailing list, see `Contact'