1 collectd - System information collection daemon
2 =================================================
3 http://collectd.org/
5 About
6 -----
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
10 ways.
13 Features
14 --------
16 * collectd is able to collect the following data:
18 - apache
19 Apache server utilization: Number of bytes transfered, number of
20 requests handled and detailed scoreboard statistics
22 - apcups
23 APC UPS Daemon: UPS charge, load, input/output/battery voltage, etc.
25 - apple_sensors
26 Sensors in Macs running Mac OS X / Darwin: Temperature, fanspeed and
27 voltage sensors.
29 - ascent
30 Statistics about Ascent, a free server for the game `World of Warcraft'.
32 - battery
33 Batterycharge, -current and voltage of ACPI and PMU based laptop
34 batteries.
36 - bind
37 Name server and resolver statistics from the `statistics-channel'
38 interface of BIND 9.5, 9,6 and later.
40 - conntrack
41 Number of nf_conntrack entries.
43 - contextswitch
44 Number of context switches done by the operating system.
46 - cpu
47 CPU utilization: Time spent in the system, user, nice, idle, and related
48 states.
50 - cpufreq
51 CPU frequency (For laptops with speed step or a similar technology)
53 - curl
54 Parse statistics from websites using regular expressions.
56 - curl_json
57 Retrieves JSON data via cURL and parses it according to user
58 configuration.
60 - curl_xml
61 Retrieves XML data via cURL and parses it according to user
62 configuration.
64 - dbi
65 Executes SQL statements on various databases and interprets the returned
66 data.
68 - df
69 Mountpoint usage (Basically the values `df(1)' delivers)
71 - disk
72 Disk utilization: Sectors read/written, number of read/write actions,
73 average time an IO-operation took to complete.
75 - dns
76 DNS traffic: Query types, response codes, opcodes and traffic/octets
77 transfered.
79 - email
80 Email statistics: Count, traffic, spam scores and checks.
81 See collectd-email(5).
83 - entropy
84 Amount of entropy available to the system.
86 - ethstat
87 Network interface card statistics.
89 - exec
90 Values gathered by a custom program or script.
91 See collectd-exec(5).
93 - filecount
94 Count the number of files in directories.
96 - fscache
97 Linux file-system based caching framework statistics.
99 - gmond
100 Receive multicast traffic from Ganglia instances.
102 - hddtemp
103 Harddisk temperatures using hddtempd.
105 - interface
106 Interface traffic: Number of octets, packets and errors for each
107 interface.
109 - iptables
110 Iptables' counters: Number of bytes that were matched by a certain
111 iptables rule.
113 - ipmi
114 IPMI (Intelligent Platform Management Interface) sensors information.
116 - ipvs
117 IPVS connection statistics (number of connections, octets and packets
118 for each service and destination).
119 See http://www.linuxvirtualserver.org/software/index.html.
121 - irq
122 IRQ counters: Frequency in which certain interrupts occur.
124 - java
125 Integrates a `Java Virtual Machine' (JVM) to execute plugins in Java
126 bytecode. See “Configuring with libjvm” below.
128 - load
129 System load average over the last 1, 5 and 15 minutes.
131 - lpar
132 Detailed CPU statistics of the “Logical Partitions” virtualization
133 technique built into IBM's POWER processors.
135 - libvirt
136 CPU, memory, disk and network I/O statistics from virtual machines.
138 - madwifi
139 Queries very detailed usage statistics from wireless LAN adapters and
140 interfaces that use the Atheros chipset and the MadWifi driver.
142 - mbmon
143 Motherboard sensors: temperature, fanspeed and voltage information,
144 using mbmon(1).
146 - md
147 Linux software-RAID device information (number of active, failed, spare
148 and missing disks).
150 - memcachec
151 Query and parse data from a memcache daemon (memcached).
153 - memcached
154 Statistics of the memcached distributed caching system.
155 <http://www.danga.com/memcached/>
157 - memory
158 Memory utilization: Memory occupied by running processes, page cache,
159 buffer cache and free.
161 - mic
162 Collects CPU usage, memory usage and temperatures from Intel Many
163 Integrated Core (MIC) CPUs.
165 - modbus
166 Reads values from Modbus/TCP enabled devices. Supports reading values
167 from multiple "slaves" so gateway devices can be used.
169 - multimeter
170 Information provided by serial multimeters, such as the `Metex
171 M-4650CR'.
173 - mysql
174 MySQL server statistics: Commands issued, handlers triggered, thread
175 usage, query cache utilization and traffic/octets sent and received.
177 - netapp
178 Plugin to query performance values from a NetApp storage system using the
179 “Manage ONTAP” SDK provided by NetApp.
181 - netlink
182 Very detailed Linux network interface and routing statistics. You can get
183 (detailed) information on interfaces, qdiscs, classes, and, if you can
184 make use of it, filters.
186 - network
187 Receive values that were collected by other hosts. Large setups will
188 want to collect the data on one dedicated machine, and this is the
189 plugin of choice for that.
191 - nfs
192 NFS Procedures: Which NFS command were called how often. Only NFSv2 and
193 NFSv3 right now.
195 - nginx
196 Collects statistics from `nginx' (speak: engine X), a HTTP and mail
197 server/proxy.
199 - ntpd
200 NTP daemon statistics: Local clock drift, offset to peers, etc.
202 - nut
203 Network UPS tools: UPS current, voltage, power, charge, utilisation,
204 temperature, etc. See upsd(8).
206 - numa
207 Information about Non-Uniform Memory Access (NUMA).
209 - olsrd
210 Queries routing information from the “Optimized Link State Routing”
211 daemon.
213 - onewire (EXPERIMENTAL!)
214 Read onewire sensors using the owcapu library of the owfs project.
215 Please read in collectd.conf(5) why this plugin is experimental.
217 - openvpn
218 RX and TX of each client in openvpn-status.log (status-version 2).
219 <http://openvpn.net/index.php/documentation/howto.html>
221 - oracle
222 Query data from an Oracle database.
224 - perl
225 The perl plugin implements a Perl-interpreter into collectd. You can
226 write your own plugins in Perl and return arbitrary values using this
227 API. See collectd-perl(5).
229 - pf
230 Query statistics from BSD's packet filter "pf".
232 - pinba
233 Receive and dispatch timing values from Pinba, a profiling extension for
234 PHP.
236 - ping
237 Network latency: Time to reach the default gateway or another given
238 host.
240 - postgresql
241 PostgreSQL database statistics: active server connections, transaction
242 numbers, block IO, table row manipulations.
244 - powerdns
245 PowerDNS name server statistics.
247 - processes
248 Process counts: Number of running, sleeping, zombie, ... processes.
250 - protocols
251 Counts various aspects of network protocols such as IP, TCP, UDP, etc.
253 - python
254 The python plugin implements a Python interpreter into collectd. This
255 makes it possible to write plugins in Python which are executed by
256 collectd without the need to start a heavy interpreter every interval.
257 See collectd-python(5) for details.
259 - redis
260 The redis plugin gathers information from a redis server, including:
261 uptime, used memory, total connections etc.
263 - routeros
264 Query interface and wireless registration statistics from RouterOS.
266 - rrdcached
267 RRDtool caching daemon (RRDcacheD) statistics.
269 - sensors
270 System sensors, accessed using lm_sensors: Voltages, temperatures and
271 fan rotation speeds.
273 - serial
274 RX and TX of serial interfaces. Linux only; needs root privileges.
276 - snmp
277 Read values from SNMP (Simple Network Management Protocol) enabled
278 network devices such as switches, routers, thermometers, rack monitoring
279 servers, etc. See collectd-snmp(5).
281 - swap
282 Pages swapped out onto harddisk or whatever is called `swap' by the OS..
284 - table
285 Parse table-like structured files.
287 - tail
288 Follows (tails) logfiles, parses them by lines and submits matched
289 values.
291 - tail_csv
292 Follows (tails) files in CSV format, parses each line and submits
293 extracted values.
295 - tape
296 Bytes and operations read and written on tape devices. Solaris only.
298 - tcpconns
299 Number of TCP connections to specific local and remote ports.
301 - teamspeak2
302 TeamSpeak2 server statistics.
304 - ted
305 Plugin to read values from `The Energy Detective' (TED).
307 - thermal
308 Linux ACPI thermal zone information.
310 - tokyotyrant
311 Reads the number of records and file size from a running Tokyo Tyrant
312 server.
314 - uptime
315 System uptime statistics.
317 - users
318 Users currently logged in.
320 - varnish
321 Various statistics from Varnish, an HTTP accelerator.
323 - vmem
324 Virtual memory statistics, e. g. the number of page-ins/-outs or the
325 number of pagefaults.
327 - vserver
328 System resources used by Linux VServers.
329 See <http://linux-vserver.org/>.
331 - wireless
332 Link quality of wireless cards. Linux only.
334 - xmms
335 Bitrate and frequency of music played with XMMS.
337 - zfs_arc
338 Statistics for ZFS' “Adaptive Replacement Cache” (ARC).
340 * Output can be written or sent to various destinations by the following
341 plugins:
343 - amqp
344 Sends JSON-encoded data to an Advanced Message Queuing Protocol (AMQP)
345 server, such as RabbitMQ.
347 - csv
348 Write to comma separated values (CSV) files. This needs lots of
349 diskspace but is extremely portable and can be analysed with almost
350 every program that can analyse anything. Even Microsoft's Excel..
352 - network
353 Send the data to a remote host to save the data somehow. This is useful
354 for large setups where the data should be saved by a dedicated machine.
356 - perl
357 Of course the values are propagated to plugins written in Perl, too, so
358 you can easily do weird stuff with the plugins we didn't dare think of
359 ;) See collectd-perl(5).
361 - python
362 It's possible to implement write plugins in Python using the python
363 plugin. See collectd-python(5) for details.
365 - rrdcached
366 Output to round-robin-database (RRD) files using the RRDtool caching
367 daemon (RRDcacheD) - see rrdcached(1). That daemon provides a general
368 implementation of the caching done by the `rrdtool' plugin.
370 - rrdtool
371 Output to round-robin-database (RRD) files using librrd. See rrdtool(1).
372 This is likely the most popular destination for such values. Since
373 updates to RRD-files are somewhat expensive this plugin can cache
374 updates to the files and write a bunch of updates at once, which lessens
375 system load a lot.
377 - unixsock
378 One can query the values from the unixsock plugin whenever they're
379 needed. Please read collectd-unixsock(5) for a description on how that's
380 done.
382 - write_graphite
383 Sends data to Carbon, the storage layer of Graphite.
385 - write_http
386 Sends the values collected by collectd to a web-server using HTTP POST
387 requests. The transmitted data is either in a form understood by the
388 Exec plugin or formatted in JSON.
390 - write_mongodb
391 Sends data to MongoDB, a NoSQL database.
393 - write_redis
394 Sends the values to a Redis key-value database server.
396 - write_riemann
397 Sends data to Riemann, a stream processing and monitoring system.
399 * Logging is, as everything in collectd, provided by plugins. The following
400 plugins keep up informed about what's going on:
402 - logfile
403 Writes logmessages to a file or STDOUT/STDERR.
405 - perl
406 Log messages are propagated to plugins written in Perl as well.
407 See collectd-perl(5).
409 - python
410 It's possible to implement log plugins in Python using the python plugin.
411 See collectd-python(5) for details.
413 - syslog
414 Logs to the standard UNIX logging mechanism, syslog.
416 * Notifications can be handled by the following plugins:
418 - notify_desktop
419 Send a desktop notification to a notification daemon, as defined in
420 the Desktop Notification Specification. To actually display the
421 notifications, notification-daemon is required.
422 See http://www.galago-project.org/specs/notification/.
424 - notify_email
425 Send an E-mail with the notification message to the configured
426 recipients.
428 - exec
429 Execute a program or script to handle the notification.
430 See collectd-exec(5).
432 - logfile
433 Writes the notification message to a file or STDOUT/STDERR.
435 - network
436 Send the notification to a remote host to handle it somehow.
438 - perl
439 Notifications are propagated to plugins written in Perl as well.
440 See collectd-perl(5).
442 - python
443 It's possible to implement notification plugins in Python using the
444 python plugin. See collectd-python(5) for details.
446 * Value processing can be controlled using the "filter chain" infrastructure
447 and "matches" and "targets". The following plugins are available:
449 - match_empty_counter
450 Match counter values which are currently zero.
452 - match_hashed
453 Match values using a hash function of the hostname.
455 - match_regex
456 Match values by their identifier based on regular expressions.
458 - match_timediff
459 Match values with an invalid timestamp.
461 - match_value
462 Select values by their data sources' values.
464 - target_notification
465 Create and dispatch a notification.
467 - target_replace
468 Replace parts of an identifier using regular expressions.
470 - target_scale
471 Scale (multiply) values by an arbitrary value.
473 - target_set
474 Set (overwrite) entire parts of an identifier.
476 * Miscellaneous plugins:
478 - aggregation
479 Selects multiple value lists based on patterns or regular expressions
480 and creates new aggregated values lists from those.
482 - threshold
483 Checks values against configured thresholds and creates notifications if
484 values are out of bounds. See collectd-threshold(5) for details.
486 - uuid
487 Sets the hostname to an unique identifier. This is meant for setups
488 where each client may migrate to another physical host, possibly going
489 through one or more name changes in the process.
491 * Performance: Since collectd is running as a daemon it doesn't spend much
492 time starting up again and again. With the exception of the exec plugin no
493 processes are forked. Caching in output plugins, such as the rrdtool and
494 network plugins, makes sure your resources are used efficiently. Also,
495 since collectd is programmed multithreaded it benefits from hyperthreading
496 and multicore processors and makes sure that the daemon isn't idle if only
497 one plugin waits for an IO-operation to complete.
499 * Once set up, hardly any maintenance is necessary. Setup is kept as easy
500 as possible and the default values should be okay for most users.
503 Operation
504 ---------
506 * collectd's configuration file can be found at `sysconfdir'/collectd.conf.
507 Run `collectd -h' for a list of builtin defaults. See `collectd.conf(5)'
508 for a list of options and a syntax description.
510 * When the `csv' or `rrdtool' plugins are loaded they'll write the values to
511 files. The usual place for these files is beneath `/var/lib/collectd'.
513 * When using some of the plugins, collectd needs to run as user root, since
514 only root can do certain things, such as craft ICMP packages needed to ping
515 other hosts. collectd should NOT be installed setuid root since it can be
516 used to overwrite valuable files!
518 * Sample scripts to generate graphs reside in `contrib/' in the source
519 package or somewhere near `/usr/share/doc/collectd' in most distributions.
520 Please be aware that those script are meant as a starting point for your
521 own experiments.. Some of them require the `RRDs' Perl module.
522 (`librrds-perl' on Debian) If you have written a more sophisticated
523 solution please share it with us.
525 * The RRAs of the automatically created RRD files depend on the `step'
526 and `heartbeat' settings given. If change these settings you may need to
527 re-create the files, losing all data. Please be aware of that when changing
528 the values and read the rrdtool(1) manpage thoroughly.
531 collectd and chkrootkit
532 -----------------------
534 If you are using the `dns' plugin chkrootkit(1) will report collectd as a
535 packet sniffer ("<iface>: PACKET SNIFFER(/usr/sbin/collectd[<pid>])"). The
536 plugin captures all UDP packets on port 53 to analyze the DNS traffic. In
537 this case, collectd is a legitimate sniffer and the report should be
538 considered to be a false positive. However, you might want to check that
539 this really is collectd and not some other, illegitimate sniffer.
542 Prerequisites
543 -------------
545 To compile collectd from source you will need:
547 * Usual suspects: C compiler, linker, preprocessor, make, ...
549 * A POSIX-threads (pthread) implementation.
550 Since gathering some statistics is slow (network connections, slow devices,
551 etc) the collectd is parallelized. The POSIX threads interface is being
552 used and should be found in various implementations for hopefully all
553 platforms.
555 * CoreFoundation.framework and IOKit.framework (optional)
556 For compiling on Darwin in general and the `apple_sensors' plugin in
557 particular.
558 <http://developer.apple.com/corefoundation/>
560 * libclntsh (optional)
561 Used by the `oracle' plugin.
563 * libcredis (optional)
564 Used by the redis plugin. Please note that you require a 0.2.2 version
565 or higher. <http://code.google.com/p/credis/>
567 * libcurl (optional)
568 If you want to use the `apache', `ascent', `curl', `nginx', or `write_http'
569 plugin.
570 <http://curl.haxx.se/>
572 * libdbi (optional)
573 Used by the `dbi' plugin to connect to various databases.
574 <http://libdbi.sourceforge.net/>
576 * libesmtp (optional)
577 For the `notify_email' plugin.
578 <http://www.stafford.uklinux.net/libesmtp/>
580 * libganglia (optional)
581 Used by the `gmond' plugin to process data received from Ganglia.
582 <http://ganglia.info/>
584 * libgcrypt (optional)
585 Used by the `network' plugin for encryption and authentication.
586 <http://www.gnupg.org/>
588 * libhal (optional)
589 If present, the uuid plugin will check for UUID from HAL.
590 <http://hal.freedesktop.org/>
592 * libiptc (optional)
593 For querying iptables counters.
594 <http://netfilter.org/>
596 If not found on the system, a version shipped with this distribution can
597 be used. It requires some Linux headers in /usr/include/linux. You can
598 force the build system to use the shipped version by specifying
599 --with-libiptc=shipped
600 when running the configure script.
602 * libjvm (optional)
603 Library that encapsulates the `Java Virtual Machine' (JVM). This library is
604 used by the Java plugin to execute Java bytecode. See “Configuring with
605 libjvm” below.
606 <http://openjdk.java.net/> (and others)
608 * libmemcached (optional)
609 Used by the `memcachec' plugin to connect to a memcache daemon.
610 <http://tangent.org/552/libmemcached.html>
612 * libmodbus (optional)
613 Used by the “modbus” plugin to communicate with Modbus/TCP devices. The
614 “modbus” plugin works with version 2.0.3 of the library – due to frequent
615 API changes other versions may or may not compile cleanly.
616 <http://www.libmodbus.org/>
618 * libmysqlclient (optional)
619 Unsurprisingly used by the `mysql' plugin.
620 <http://dev.mysql.com/>
622 * libnetapp (optional)
623 Required for the “netapp” plugin.
624 This library is part of the “Manage ONTAP SDK” published by NetApp.
626 * libnetlink (optional)
627 Used, obviously, for the `netlink' plugin.
628 <http://www.linuxfoundation.org/en/Net:Iproute2>
630 * libnetsnmp (optional)
631 For the `snmp' plugin.
632 <http://www.net-snmp.org/>
634 * libnotify (optional)
635 For the `notify_desktop' plugin.
636 <http://www.galago-project.org/>
638 * liboping (optional)
639 Used by the `ping' plugin to send and receive ICMP packets.
640 <http://verplant.org/liboping/>
642 * libowcapi (optional)
643 Used by the `onewire' plugin to read values from onewire sensors (or the
644 owserver(1) daemon).
645 <http://www.owfs.org/>
647 * libpcap (optional)
648 Used to capture packets by the `dns' plugin.
649 <http://www.tcpdump.org/>
651 * libperfstat (optional)
652 Used by various plugins to gather statistics under AIX.
654 * libperl (optional)
655 Obviously used by the `perl' plugin. The library has to be compiled with
656 ithread support (introduced in Perl 5.6.0).
657 <http://www.perl.org/>
659 * libpq (optional)
660 The PostgreSQL C client library used by the `postgresql' plugin.
661 <http://www.postgresql.org/>
663 * libprotobuf-c, protoc-c (optional)
664 Used by the `pinba' plugin to generate a parser for the network packets
665 sent by the Pinba PHP extension.
666 <http://code.google.com/p/protobuf-c/>
668 * libpython (optional)
669 Used by the `python' plugin. Currently, Python 2.3 and later and Python 3
670 are supported.
671 <http://www.python.org/>
673 * librabbitmq (optional; also called “rabbitmq-c”)
674 Used by the AMQP plugin for AMQP connections, for example to RabbitMQ.
675 <http://hg.rabbitmq.com/rabbitmq-c/>
677 * librouteros (optional)
678 Used by the `routeros' plugin to connect to a device running `RouterOS'.
679 <http://verplant.org/librouteros/>
681 * librrd (optional)
682 Used by the `rrdtool' and `rrdcached' plugins. The latter requires RRDtool
683 client support which was added after version 1.3 of RRDtool. Versions 1.0,
684 1.2 and 1.3 are known to work with the `rrdtool' plugin.
685 <http://oss.oetiker.ch/rrdtool/>
687 * librt, libsocket, libkstat, libdevinfo (optional)
688 Various standard Solaris libraries which provide system functions.
689 <http://developers.sun.com/solaris/>
691 * libsensors (optional)
692 To read from `lm_sensors', see the `sensors' plugin.
693 <http://www.lm-sensors.org/>
695 * libstatgrab (optional)
696 Used by various plugins to collect statistics on systems other than Linux
697 and/or Solaris.
698 <http://www.i-scream.org/libstatgrab/>
700 * libtokyotyrant (optional)
701 Used by the tokyotyrant plugin.
702 <http://1978th.net/tokyotyrant/>
704 * libupsclient/nut (optional)
705 For the `nut' plugin which queries nut's `upsd'.
706 <http://networkupstools.org/>
708 * libvirt (optional)
709 Collect statistics from virtual machines.
710 <http://libvirt.org/>
712 * libxml2 (optional)
713 Parse XML data. This is needed for the `ascent' and `libvirt' plugins.
714 <http://xmlsoft.org/>
716 * libxmms (optional)
717 <http://www.xmms.org/>
719 * libyajl (optional)
720 Parse JSON data. This is needed for the `curl_json' plugin.
721 <http://github.com/lloyd/yajl>
723 * libvarnish (optional)
724 Fetches statistics from a Varnish instance. This is needed for the Varnish plugin
725 <http://varnish-cache.org>
727 Configuring / Compiling / Installing
728 ------------------------------------
730 To configure, build and install collectd with the default settings, run
731 `./configure && make && make install'. For detailed, generic instructions
732 see INSTALL. For a complete list of configure options and their description,
733 run `./configure --help'.
735 By default, the configure script will check for all build dependencies and
736 disable all plugins whose requirements cannot be fulfilled (any other plugin
737 will be enabled). To enable a plugin, install missing dependencies (see
738 section `Prerequisites' above) and rerun `configure'. If you specify the
739 `--enable-<plugin>' configure option, the script will fail if the depen-
740 dencies for the specified plugin are not met. In that case you can force the
741 plugin to be built using the `--enable-<plugin>=force' configure option.
742 This will most likely fail though unless you're working in a very unusual
743 setup and you really know what you're doing. If you specify the
744 `--disable-<plugin>' configure option, the plugin will not be built. If you
745 specify the `--enable-all-plugins' or `--disable-all-plugins' configure
746 options, all plugins will be enabled or disabled respectively by default.
747 Explicitly enabling or disabling a plugin overwrites the default for the
748 specified plugin. These options are meant for package maintainers and should
749 not be used in everyday situations.
751 By default, collectd will be installed into `/opt/collectd'. You can adjust
752 this setting by specifying the `--prefix' configure option - see INSTALL for
753 details. If you pass DESTDIR=<path> to `make install', <path> will be
754 prefixed to all installation directories. This might be useful when creating
755 packages for collectd.
757 Configuring with libjvm
758 -----------------------
760 To determine the location of the required files of a Java installation is not
761 an easy task, because the locations vary with your kernel (Linux, SunOS, …)
762 and with your architecture (x86, SPARC, …) and there is no ‘java-config’
763 script we could use. Configuration of the JVM library is therefore a bit
764 tricky.
766 The easiest way to use the `--with-java=$JAVA_HOME' option, where
767 `$JAVA_HOME' is usually something like:
768 /usr/lib/jvm/java-1.5.0-sun-1.5.0.14
770 The configure script will then use find(1) to look for the following files:
772 - jni.h
773 - jni_md.h
774 - libjvm.so
776 If found, appropriate CPP-flags and LD-flags are set and the following
777 library checks succeed.
779 If this doesn't work for you, you have the possibility to specify CPP-flags,
780 C-flags and LD-flags for the ‘Java’ plugin by hand, using the following three
781 (environment) variables:
783 - JAVA_CPPFLAGS
784 - JAVA_CFLAGS
785 - JAVA_LDFLAGS
787 For example (shortened for demonstration purposes):
789 ./configure JAVA_CPPFLAGS="-I$JAVA_HOME/include -I$JAVA_HOME/include/linux"
791 Adding "-ljvm" to the JAVA_LDFLAGS is done automatically, you don't have to
792 do that.
794 Crosscompiling
795 --------------
797 To compile correctly collectd needs to be able to initialize static
798 variables to NAN (Not A Number). Some C libraries, especially the GNU
799 libc, have a problem with that.
801 Luckily, with GCC it's possible to work around that problem: One can define
802 NAN as being (0.0 / 0.0) and `isnan' as `f != f'. However, to test this
803 ``implementation'' the configure script needs to compile and run a short
804 test program. Obviously running a test program when doing a cross-
805 compilation is, well, challenging.
807 If you run into this problem, you can use the `--with-nan-emulation'
808 configure option to force the use of this implementation. We can't promise
809 that the compiled binary actually behaves as it should, but since NANs
810 are likely never passed to the libm you have a good chance to be lucky.
812 Likewise, collectd needs to know the layout of doubles in memory, in order
813 to craft uniform network packets over different architectures. For this, it
814 needs to know how to convert doubles into the memory layout used by x86. The
815 configure script tries to figure this out by compiling and running a few
816 small test programs. This is of course not possible when cross-compiling.
817 You can use the `--with-fp-layout' option to tell the configure script which
818 conversion method to assume. Valid arguments are:
820 * `nothing' (12345678 -> 12345678)
821 * `endianflip' (12345678 -> 87654321)
822 * `intswap' (12345678 -> 56781234)
825 Contact
826 -------
828 For questions, bug reports, development information and basically all other
829 concerns please send an email to collectd's mailing list at
830 <collectd at verplant.org>.
832 For live discussion and more personal contact visit us in IRC, we're in
833 channel #collectd on freenode.
836 Author
837 ------
839 Florian octo Forster <octo at verplant.org>,
840 Sebastian tokkee Harl <sh at tokkee.org>,
841 and many contributors (see `AUTHORS').
843 Please send bug reports and patches to the mailing list, see `Contact'
844 above.