collectd - System information collection daemon ================================================= https://collectd.org/ About ----- collectd is a small daemon which collects system information periodically and provides mechanisms to store and monitor the values in a variety of ways. Features -------- * collectd is able to collect the following data: - apache Apache server utilization: Number of bytes transferred, number of requests handled and detailed scoreboard statistics - apcups APC UPS Daemon: UPS charge, load, input/output/battery voltage, etc. - apple_sensors Sensors in Macs running Mac OS X / Darwin: Temperature, fan speed and voltage sensors. - aquaero Various sensors in the Aquaero 5 water cooling board made by Aquacomputer. - ascent Statistics about Ascent, a free server for the game `World of Warcraft'. - barometer Reads absolute barometric pressure, air pressure reduced to sea level and temperature. Supported sensors are MPL115A2 and MPL3115 from Freescale and BMP085 from Bosch. - battery Batterycharge, -current and voltage of ACPI and PMU based laptop batteries. - bind Name server and resolver statistics from the `statistics-channel' interface of BIND 9.5, 9,6 and later. - ceph Statistics from the Ceph distributed storage system. - cgroups CPU accounting information for process groups under Linux. - chrony Chrony daemon statistics: Local clock drift, offset to peers, etc. - conntrack Number of nf_conntrack entries. - contextswitch Number of context switches done by the operating system. - cpu CPU utilization: Time spent in the system, user, nice, idle, and related states. - cpufreq CPU frequency (For laptops with speed step or a similar technology) - cpusleep CPU sleep: Time spent in suspend (For mobile devices which enter suspend automatically) - curl Parse statistics from websites using regular expressions. - curl_json Retrieves JSON data via cURL and parses it according to user configuration. - curl_xml Retrieves XML data via cURL and parses it according to user configuration. - dbi Executes SQL statements on various databases and interprets the returned data. - df Mountpoint usage (Basically the values `df(1)' delivers) - disk Disk utilization: Sectors read/written, number of read/write actions, average time an IO-operation took to complete. - dns DNS traffic: Query types, response codes, opcodes and traffic/octets transferred. - dpdkstat Collect DPDK interface statistics. See docs/BUILD.dpdkstat.md for detailed build instructions. - drbd Collect individual drbd resource statistics. - email Email statistics: Count, traffic, spam scores and checks. See collectd-email(5). - entropy Amount of entropy available to the system. - ethstat Network interface card statistics. - exec Values gathered by a custom program or script. See collectd-exec(5). - fhcount File handles statistics. - filecount Count the number of files in directories. - fscache Linux file-system based caching framework statistics. - gmond Receive multicast traffic from Ganglia instances. - gps Monitor gps related data through gpsd. - hddtemp Hard disk temperatures using hddtempd. - hugepages Report the number of used and free hugepages. More info on hugepages can be found here: https://www.kernel.org/doc/Documentation/vm/hugetlbpage.txt. - intel_pmu The intel_pmu plugin reads performance counters provided by the Linux kernel perf interface. The plugin uses jevents library to resolve named events to perf events and access perf interface. - intel_rdt The intel_rdt plugin collects information provided by monitoring features of Intel Resource Director Technology (Intel(R) RDT) like Cache Monitoring Technology (CMT), Memory Bandwidth Monitoring (MBM). These features provide information about utilization of shared resources like last level cache occupancy, local memory bandwidth usage, remote memory bandwidth usage, instructions per clock. - interface Interface traffic: Number of octets, packets and errors for each interface. - ipc IPC counters: semaphores used, number of allocated segments in shared memory and more. - ipmi IPMI (Intelligent Platform Management Interface) sensors information. - iptables Iptables' counters: Number of bytes that were matched by a certain iptables rule. - ipvs IPVS connection statistics (number of connections, octets and packets for each service and destination). See http://www.linuxvirtualserver.org/software/index.html. - irq IRQ counters: Frequency in which certain interrupts occur. - java Integrates a `Java Virtual Machine' (JVM) to execute plugins in Java bytecode. See docs/BUILD.java.md for detailed build instructions. - load System load average over the last 1, 5 and 15 minutes. - lpar Detailed CPU statistics of the “Logical Partitions” virtualization technique built into IBM's POWER processors. - lua The Lua plugin implements a Lua interpreter into collectd. This makes it possible to write plugins in Lua which are executed by collectd without the need to start a heavy interpreter every interval. See collectd-lua(5) for details. - lvm Size of “Logical Volumes” (LV) and “Volume Groups” (VG) of Linux' “Logical Volume Manager” (LVM). - madwifi Queries very detailed usage statistics from wireless LAN adapters and interfaces that use the Atheros chipset and the MadWifi driver. - mbmon Motherboard sensors: temperature, fan speed and voltage information, using mbmon(1). - mcelog Monitor machine check exceptions (hardware errors detected by hardware and reported to software) reported by mcelog and generate appropriate notifications when machine check exceptions are detected. - md Linux software-RAID device information (number of active, failed, spare and missing disks). - memcachec Query and parse data from a memcache daemon (memcached). - memcached Statistics of the memcached distributed caching system. - memory Memory utilization: Memory occupied by running processes, page cache, buffer cache and free. - mic Collects CPU usage, memory usage, temperatures and power consumption from Intel Many Integrated Core (MIC) CPUs. - modbus Reads values from Modbus/TCP enabled devices. Supports reading values from multiple "slaves" so gateway devices can be used. - multimeter Information provided by serial multimeters, such as the `Metex M-4650CR'. - mysql MySQL server statistics: Commands issued, handlers triggered, thread usage, query cache utilization and traffic/octets sent and received. - netapp Plugin to query performance values from a NetApp storage system using the “Manage ONTAP” SDK provided by NetApp. - netlink Very detailed Linux network interface and routing statistics. You can get (detailed) information on interfaces, qdiscs, classes, and, if you can make use of it, filters. - network Receive values that were collected by other hosts. Large setups will want to collect the data on one dedicated machine, and this is the plugin of choice for that. - nfs NFS Procedures: Which NFS command were called how often. - nginx Collects statistics from `nginx' (speak: engine X), a HTTP and mail server/proxy. - ntpd NTP daemon statistics: Local clock drift, offset to peers, etc. - numa Information about Non-Uniform Memory Access (NUMA). - nut Network UPS tools: UPS current, voltage, power, charge, utilisation, temperature, etc. See upsd(8). - olsrd Queries routing information from the “Optimized Link State Routing” daemon. - onewire (EXPERIMENTAL!) Read onewire sensors using the owcapu library of the owfs project. Please read in collectd.conf(5) why this plugin is experimental. - openldap Read monitoring information from OpenLDAP's cn=Monitor subtree. - openvpn RX and TX of each client in openvpn-status.log (status-version 2). - oracle Query data from an Oracle database. - ovs_events The plugin monitors the link status of Open vSwitch (OVS) connected interfaces, dispatches the values to collectd and sends the notification whenever the link state change occurs in the OVS database. It requires YAJL library to be installed. Detailed instructions for installing and setting up Open vSwitch, see OVS documentation. - ovs_stats The plugin collects the statistics of OVS connected bridges and interfaces. It requires YAJL library to be installed. Detailed instructions for installing and setting up Open vSwitch, see OVS documentation. - perl The perl plugin implements a Perl-interpreter into collectd. You can write your own plugins in Perl and return arbitrary values using this API. See collectd-perl(5). - pf Query statistics from BSD's packet filter "pf". - pinba Receive and dispatch timing values from Pinba, a profiling extension for PHP. - ping Network latency: Time to reach the default gateway or another given host. - postgresql PostgreSQL database statistics: active server connections, transaction numbers, block IO, table row manipulations. - powerdns PowerDNS name server statistics. - processes Process counts: Number of running, sleeping, zombie, ... processes. - protocols Counts various aspects of network protocols such as IP, TCP, UDP, etc. - python The python plugin implements a Python interpreter into collectd. This makes it possible to write plugins in Python which are executed by collectd without the need to start a heavy interpreter every interval. See collectd-python(5) for details. - redis The redis plugin gathers information from a Redis server, including: uptime, used memory, total connections etc. - routeros Query interface and wireless registration statistics from RouterOS. - rrdcached RRDtool caching daemon (RRDcacheD) statistics. - sensors System sensors, accessed using lm_sensors: Voltages, temperatures and fan rotation speeds. - serial RX and TX of serial interfaces. Linux only; needs root privileges. - sigrok Uses libsigrok as a backend, allowing any sigrok-supported device to have its measurements fed to collectd. This includes multimeters, sound level meters, thermometers, and much more. - smart Collect SMART statistics, notably load cycle count, temperature and bad sectors. - snmp Read values from SNMP (Simple Network Management Protocol) enabled network devices such as switches, routers, thermometers, rack monitoring servers, etc. See collectd-snmp(5). - statsd Acts as a StatsD server, reading values sent over the network from StatsD clients and calculating rates and other aggregates out of these values. - swap Pages swapped out onto hard disk or whatever is called `swap' by the OS.. - table Parse table-like structured files. - tail Follows (tails) log files, parses them by lines and submits matched values. - tail_csv Follows (tails) files in CSV format, parses each line and submits extracted values. - tape Bytes and operations read and written on tape devices. Solaris only. - tcpconns Number of TCP connections to specific local and remote ports. - teamspeak2 TeamSpeak2 server statistics. - ted Plugin to read values from `The Energy Detective' (TED). - thermal Linux ACPI thermal zone information. - tokyotyrant Reads the number of records and file size from a running Tokyo Tyrant server. - turbostat Reads CPU frequency and C-state residency on modern Intel turbo-capable processors. - uptime System uptime statistics. - users Users currently logged in. - varnish Various statistics from Varnish, an HTTP accelerator. - virt CPU, memory, disk and network I/O statistics from virtual machines. - vmem Virtual memory statistics, e.g. the number of page-ins/-outs or the number of pagefaults. - vserver System resources used by Linux VServers. See . - wireless Link quality of wireless cards. Linux only. - xencpu XEN Hypervisor CPU stats. - xmms Bitrate and frequency of music played with XMMS. - zfs_arc Statistics for ZFS' “Adaptive Replacement Cache” (ARC). - zone Measures the percentage of cpu load per container (zone) under Solaris 10 and higher - zookeeper Read data from Zookeeper's MNTR command. * Output can be written or sent to various destinations by the following plugins: - amqp Sends JSON-encoded data to an Advanced Message Queuing Protocol (AMQP) server, such as RabbitMQ. - csv Write to comma separated values (CSV) files. This needs lots of diskspace but is extremely portable and can be analysed with almost every program that can analyse anything. Even Microsoft's Excel.. - grpc Send and receive values over the network using the gRPC framework. - lua It's possible to implement write plugins in Lua using the Lua plugin. See collectd-lua(5) for details. - mqtt Publishes and subscribes to MQTT topics. - network Send the data to a remote host to save the data somehow. This is useful for large setups where the data should be saved by a dedicated machine. - perl Of course the values are propagated to plugins written in Perl, too, so you can easily do weird stuff with the plugins we didn't dare think of ;) See collectd-perl(5). - python It's possible to implement write plugins in Python using the python plugin. See collectd-python(5) for details. - rrdcached Output to round-robin-database (RRD) files using the RRDtool caching daemon (RRDcacheD) - see rrdcached(1). That daemon provides a general implementation of the caching done by the `rrdtool' plugin. - rrdtool Output to round-robin-database (RRD) files using librrd. See rrdtool(1). This is likely the most popular destination for such values. Since updates to RRD-files are somewhat expensive this plugin can cache updates to the files and write a bunch of updates at once, which lessens system load a lot. - snmp_agent Receives and handles queries from SNMP master agent and returns the data collected by read plugins. Handles requests only for OIDs specified in configuration file. To handle SNMP queries the plugin gets data from collectd and translates requested values from collectd's internal format to SNMP format. - unixsock One can query the values from the unixsock plugin whenever they're needed. Please read collectd-unixsock(5) for a description on how that's done. - write_graphite Sends data to Carbon, the storage layer of Graphite using TCP or UDP. It can be configured to avoid logging send errors (especially useful when using UDP). - write_http Sends the values collected by collectd to a web-server using HTTP POST requests. The transmitted data is either in a form understood by the Exec plugin or formatted in JSON. - write_kafka Sends data to Apache Kafka, a distributed queue. - write_log Writes data to the log - write_mongodb Sends data to MongoDB, a NoSQL database. - write_prometheus Publish values using an embedded HTTP server, in a format compatible with Prometheus' collectd_exporter. - write_redis Sends the values to a Redis key-value database server. - write_riemann Sends data to Riemann, a stream processing and monitoring system. - write_sensu Sends data to Sensu, a stream processing and monitoring system, via the Sensu client local TCP socket. - write_tsdb Sends data OpenTSDB, a scalable no master, no shared state time series database. * Logging is, as everything in collectd, provided by plugins. The following plugins keep us informed about what's going on: - logfile Writes log messages to a file or STDOUT/STDERR. - perl Log messages are propagated to plugins written in Perl as well. See collectd-perl(5). - python It's possible to implement log plugins in Python using the python plugin. See collectd-python(5) for details. - syslog Logs to the standard UNIX logging mechanism, syslog. - log_logstash Writes log messages formatted as logstash JSON events. * Notifications can be handled by the following plugins: - notify_desktop Send a desktop notification to a notification daemon, as defined in the Desktop Notification Specification. To actually display the notifications, notification-daemon is required. See http://www.galago-project.org/specs/notification/. - notify_email Send an E-mail with the notification message to the configured recipients. - notify_nagios Submit notifications as passive check results to a local nagios instance. - exec Execute a program or script to handle the notification. See collectd-exec(5). - logfile Writes the notification message to a file or STDOUT/STDERR. - network Send the notification to a remote host to handle it somehow. - perl Notifications are propagated to plugins written in Perl as well. See collectd-perl(5). - python It's possible to implement notification plugins in Python using the python plugin. See collectd-python(5) for details. * Value processing can be controlled using the "filter chain" infrastructure and "matches" and "targets". The following plugins are available: - match_empty_counter Match counter values which are currently zero. - match_hashed Match values using a hash function of the hostname. - match_regex Match values by their identifier based on regular expressions. - match_timediff Match values with an invalid timestamp. - match_value Select values by their data sources' values. - target_notification Create and dispatch a notification. - target_replace Replace parts of an identifier using regular expressions. - target_scale Scale (multiply) values by an arbitrary value. - target_set Set (overwrite) entire parts of an identifier. * Miscellaneous plugins: - aggregation Selects multiple value lists based on patterns or regular expressions and creates new aggregated values lists from those. - threshold Checks values against configured thresholds and creates notifications if values are out of bounds. See collectd-threshold(5) for details. - uuid Sets the hostname to a unique identifier. This is meant for setups where each client may migrate to another physical host, possibly going through one or more name changes in the process. * Performance: Since collectd is running as a daemon it doesn't spend much time starting up again and again. With the exception of the exec plugin no processes are forked. Caching in output plugins, such as the rrdtool and network plugins, makes sure your resources are used efficiently. Also, since collectd is programmed multithreaded it benefits from hyper-threading and multicore processors and makes sure that the daemon isn't idle if only one plugin waits for an IO-operation to complete. * Once set up, hardly any maintenance is necessary. Setup is kept as easy as possible and the default values should be okay for most users. Operation --------- * collectd's configuration file can be found at `sysconfdir'/collectd.conf. Run `collectd -h' for a list of built-in defaults. See `collectd.conf(5)' for a list of options and a syntax description. * When the `csv' or `rrdtool' plugins are loaded they'll write the values to files. The usual place for these files is beneath `/var/lib/collectd'. * When using some of the plugins, collectd needs to run as user root, since only root can do certain things, such as craft ICMP packages needed to ping other hosts. collectd should NOT be installed setuid root since it can be used to overwrite valuable files! * Sample scripts to generate graphs reside in `contrib/' in the source package or somewhere near `/usr/share/doc/collectd' in most distributions. Please be aware that those script are meant as a starting point for your own experiments.. Some of them require the `RRDs' Perl module. (`librrds-perl' on Debian) If you have written a more sophisticated solution please share it with us. * The RRAs of the automatically created RRD files depend on the `step' and `heartbeat' settings given. If change these settings you may need to re-create the files, losing all data. Please be aware of that when changing the values and read the rrdtool(1) manpage thoroughly. collectd and chkrootkit ----------------------- If you are using the `dns' plugin chkrootkit(1) will report collectd as a packet sniffer (": PACKET SNIFFER(/usr/sbin/collectd[])"). The plugin captures all UDP packets on port 53 to analyze the DNS traffic. In this case, collectd is a legitimate sniffer and the report should be considered to be a false positive. However, you might want to check that this really is collectd and not some other, illegitimate sniffer. Prerequisites ------------- To compile collectd from source you will need: * Usual suspects: C compiler, linker, preprocessor, make, ... collectd makes use of some common C99 features, e.g. compound literals and mixed declarations, and therefore requires a C99 compatible compiler. On Debian and Ubuntu, the "build-essential" package should pull in everything that's necessary. * A POSIX-threads (pthread) implementation. Since gathering some statistics is slow (network connections, slow devices, etc) collectd is parallelized. The POSIX threads interface is being used and should be found in various implementations for hopefully all platforms. * When building from the Git repository, flex (tokenizer) and bison (parser generator) are required. Release tarballs include the generated files – you don't need these packages in that case. * aerotools-ng (optional) Used by the `aquaero' plugin. Currently, the `libaquaero5' library, which is used by the `aerotools-ng' toolkit, is not compiled as a shared object nor does it feature an installation routine. Therefore, you need to point collectd's configure script at the source directory of the `aerotools-ng' project. * CoreFoundation.framework and IOKit.framework (optional) For compiling on Darwin in general and the `apple_sensors' plugin in particular. * libatasmart (optional) Used by the `smart' plugin. * libcap (optional) The `turbostat' plugin can optionally build Linux Capabilities support, which avoids full privileges requirement (aka. running as root) to read values. * libclntsh (optional) Used by the `oracle' plugin. * libhiredis (optional) Used by the redis plugin. Please note that you require a 0.10.0 version or higher. * libcurl (optional) If you want to use the `apache', `ascent', `bind', `curl', `curl_json', `curl_xml', `nginx', or `write_http' plugin. * libdbi (optional) Used by the `dbi' plugin to connect to various databases. * libesmtp (optional) For the `notify_email' plugin. * libganglia (optional) Used by the `gmond' plugin to process data received from Ganglia. * libgrpc (optional) Used by the `grpc' plugin. gRPC requires a C++ compiler supporting the C++11 standard. * libgcrypt (optional) Used by the `network' plugin for encryption and authentication. * libgps (optional) Used by the `gps' plugin. * libi2c-dev (optional) Used for the plugin `barometer', provides just the i2c-dev.h header file for user space i2c development. * libiptc (optional) For querying iptables counters. * libjevents (optional) The jevents library is used by the `intel_pmu' plugin to access the Linux kernel perf interface. Note: the library should be build with -fPIC flag to be linked with intel_pmu shared object correctly. * libjvm (optional) Library that encapsulates the `Java Virtual Machine' (JVM). This library is used by the `java' plugin to execute Java bytecode. See docs/BUILD.java.md for detailed build instructions. (and others) * libldap (optional) Used by the `openldap' plugin. * liblua (optional) Used by the `lua' plugin. Currently, Lua 5.1 and later are supported. * liblvm2 (optional) Used by the `lvm' plugin. * libmemcached (optional) Used by the `memcachec' plugin to connect to a memcache daemon. * libmicrohttpd (optional) Used by the write_prometheus plugin to run an http daemon. * libmnl (optional) Used by the `netlink' plugin. * libmodbus (optional) Used by the `modbus' plugin to communicate with Modbus/TCP devices. The `modbus' plugin works with version 2.0.3 of the library – due to frequent API changes other versions may or may not compile cleanly. * libmysqlclient (optional) Unsurprisingly used by the `mysql' plugin. * libnetapp (optional) Required for the `netapp' plugin. This library is part of the “Manage ONTAP SDK” published by NetApp. * libnetsnmp (optional) For the `snmp' and 'snmp_agent' plugins. * libnetsnmpagent (optional) Required for the 'snmp_agent' plugin. * libnotify (optional) For the `notify_desktop' plugin. * libopenipmi (optional) Used by the `ipmi' plugin to prove IPMI devices. * liboping (optional) Used by the `ping' plugin to send and receive ICMP packets. * libowcapi (optional) Used by the `onewire' plugin to read values from onewire sensors (or the owserver(1) daemon). * libpcap (optional) Used to capture packets by the `dns' plugin. * libperfstat (optional) Used by various plugins to gather statistics under AIX. * libperl (optional) Obviously used by the `perl' plugin. The library has to be compiled with ithread support (introduced in Perl 5.6.0). * libpq (optional) The PostgreSQL C client library used by the `postgresql' plugin. * libpqos (optional) The PQoS library for Intel(R) Resource Director Technology used by the `intel_rdt' plugin. * libprotobuf, protoc 3.0+ (optional) Used by the `grpc' plugin to generate service stubs and code to handle network packets of collectd's protobuf-based network protocol. * libprotobuf-c, protoc-c (optional) Used by the `pinba' plugin to generate a parser for the network packets sent by the Pinba PHP extension. * libpython (optional) Used by the `python' plugin. Currently, Python 2.6 and later and Python 3 are supported. * librabbitmq (optional; also called “rabbitmq-c”) Used by the `amqp' plugin for AMQP connections, for example to RabbitMQ. * librdkafka (optional; also called “rdkafka”) Used by the `write_kafka' plugin for producing messages and sending them to a Kafka broker. * librouteros (optional) Used by the `routeros' plugin to connect to a device running `RouterOS'. * librrd (optional) Used by the `rrdtool' and `rrdcached' plugins. The latter requires RRDtool client support which was added after version 1.3 of RRDtool. Versions 1.0, 1.2 and 1.3 are known to work with the `rrdtool' plugin. * librt, libsocket, libkstat, libdevinfo (optional) Various standard Solaris libraries which provide system functions. * libsensors (optional) To read from `lm_sensors', see the `sensors' plugin. * libsigrok (optional) Used by the `sigrok' plugin. In addition, libsigrok depends on glib, libzip, and optionally (depending on which drivers are enabled) on libusb, libftdi and libudev. * libstatgrab (optional) Used by various plugins to collect statistics on systems other than Linux and/or Solaris. * libtokyotyrant (optional) Used by the `tokyotyrant' plugin. * libupsclient/nut (optional) For the `nut' plugin which queries nut's `upsd'. * libvirt (optional) Collect statistics from virtual machines. * libxml2 (optional) Parse XML data. This is needed for the `ascent', `bind', `curl_xml' and `virt' plugins. * libxen (optional) Used by the `xencpu' plugin. * libxmms (optional) * libyajl (optional) Parse JSON data. This is needed for the `ceph', `curl_json', 'ovs_events', 'ovs_stats' and `log_logstash' plugins. * libvarnish (optional) Fetches statistics from a Varnish instance. This is needed for the `varnish' plugin. * riemann-c-client (optional) For the `write_riemann' plugin. Configuring / Compiling / Installing ------------------------------------ To configure, build and install collectd with the default settings, run `./configure && make && make install'. For detailed, generic instructions see INSTALL. For a complete list of configure options and their description, run `./configure --help'. By default, the configure script will check for all build dependencies and disable all plugins whose requirements cannot be fulfilled (any other plugin will be enabled). To enable a plugin, install missing dependencies (see section `Prerequisites' above) and rerun `configure'. If you specify the `--enable-' configure option, the script will fail if the depen- dencies for the specified plugin are not met. In that case you can force the plugin to be built using the `--enable-=force' configure option. This will most likely fail though unless you're working in a very unusual setup and you really know what you're doing. If you specify the `--disable-' configure option, the plugin will not be built. If you specify the `--enable-all-plugins' or `--disable-all-plugins' configure options, all plugins will be enabled or disabled respectively by default. Explicitly enabling or disabling a plugin overwrites the default for the specified plugin. These options are meant for package maintainers and should not be used in everyday situations. By default, collectd will be installed into `/opt/collectd'. You can adjust this setting by specifying the `--prefix' configure option - see INSTALL for details. If you pass DESTDIR= to `make install', will be prefixed to all installation directories. This might be useful when creating packages for collectd. Generating the configure script ------------------------------- Collectd ships with a `build.sh' script to generate the `configure' script shipped with releases. To generate the `configure` script, you'll need the following dependencies: - autoconf - automake - flex - bison - libtool - pkg-config The `build.sh' script takes no arguments. Crosscompiling -------------- To compile correctly collectd needs to be able to initialize static variables to NAN (Not A Number). Some C libraries, especially the GNU libc, have a problem with that. Luckily, with GCC it's possible to work around that problem: One can define NAN as being (0.0 / 0.0) and `isnan' as `f != f'. However, to test this ``implementation'' the configure script needs to compile and run a short test program. Obviously running a test program when doing a cross- compilation is, well, challenging. If you run into this problem, you can use the `--with-nan-emulation' configure option to force the use of this implementation. We can't promise that the compiled binary actually behaves as it should, but since NANs are likely never passed to the libm you have a good chance to be lucky. Likewise, collectd needs to know the layout of doubles in memory, in order to craft uniform network packets over different architectures. For this, it needs to know how to convert doubles into the memory layout used by x86. The configure script tries to figure this out by compiling and running a few small test programs. This is of course not possible when cross-compiling. You can use the `--with-fp-layout' option to tell the configure script which conversion method to assume. Valid arguments are: * `nothing' (12345678 -> 12345678) * `endianflip' (12345678 -> 87654321) * `intswap' (12345678 -> 56781234) Contact ------- Please use GitHub to report bugs and submit pull requests: . See CONTRIBUTING.md for details. For questions, development information and basically all other concerns please send an email to collectd's mailing list at . For live discussion and more personal contact visit us in IRC, we're in channel #collectd on freenode. Author ------ Florian octo Forster , Sebastian tokkee Harl , and many contributors (see `AUTHORS').