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 - cgroups
41 CPU accounting information for process groups under Linux.
43 - conntrack
44 Number of nf_conntrack entries.
46 - contextswitch
47 Number of context switches done by the operating system.
49 - cpu
50 CPU utilization: Time spent in the system, user, nice, idle, and related
51 states.
53 - cpufreq
54 CPU frequency (For laptops with speed step or a similar technology)
56 - curl
57 Parse statistics from websites using regular expressions.
59 - curl_json
60 Retrieves JSON data via cURL and parses it according to user
61 configuration.
63 - curl_xml
64 Retrieves XML data via cURL and parses it according to user
65 configuration.
67 - dbi
68 Executes SQL statements on various databases and interprets the returned
69 data.
71 - df
72 Mountpoint usage (Basically the values `df(1)' delivers)
74 - disk
75 Disk utilization: Sectors read/written, number of read/write actions,
76 average time an IO-operation took to complete.
78 - dns
79 DNS traffic: Query types, response codes, opcodes and traffic/octets
80 transfered.
82 - email
83 Email statistics: Count, traffic, spam scores and checks.
84 See collectd-email(5).
86 - entropy
87 Amount of entropy available to the system.
89 - ethstat
90 Network interface card statistics.
92 - exec
93 Values gathered by a custom program or script.
94 See collectd-exec(5).
96 - filecount
97 Count the number of files in directories.
99 - fscache
100 Linux file-system based caching framework statistics.
102 - gmond
103 Receive multicast traffic from Ganglia instances.
105 - hddtemp
106 Harddisk temperatures using hddtempd.
108 - interface
109 Interface traffic: Number of octets, packets and errors for each
110 interface.
112 - iptables
113 Iptables' counters: Number of bytes that were matched by a certain
114 iptables rule.
116 - ipmi
117 IPMI (Intelligent Platform Management Interface) sensors information.
119 - ipvs
120 IPVS connection statistics (number of connections, octets and packets
121 for each service and destination).
122 See http://www.linuxvirtualserver.org/software/index.html.
124 - irq
125 IRQ counters: Frequency in which certain interrupts occur.
127 - java
128 Integrates a `Java Virtual Machine' (JVM) to execute plugins in Java
129 bytecode. See “Configuring with libjvm” below.
131 - load
132 System load average over the last 1, 5 and 15 minutes.
134 - lpar
135 Detailed CPU statistics of the “Logical Partitions” virtualization
136 technique built into IBM's POWER processors.
138 - libvirt
139 CPU, memory, disk and network I/O statistics from virtual machines.
141 - lvm
142 Size of “Logical Volumes” (LV) and “Volume Groups” (VG) of Linux'
143 “Logical Volume Manager” (LVM).
145 - madwifi
146 Queries very detailed usage statistics from wireless LAN adapters and
147 interfaces that use the Atheros chipset and the MadWifi driver.
149 - mbmon
150 Motherboard sensors: temperature, fanspeed and voltage information,
151 using mbmon(1).
153 - md
154 Linux software-RAID device information (number of active, failed, spare
155 and missing disks).
157 - memcachec
158 Query and parse data from a memcache daemon (memcached).
160 - memcached
161 Statistics of the memcached distributed caching system.
162 <http://www.danga.com/memcached/>
164 - memory
165 Memory utilization: Memory occupied by running processes, page cache,
166 buffer cache and free.
168 - modbus
169 Reads values from Modbus/TCP enabled devices. Supports reading values
170 from multiple "slaves" so gateway devices can be used.
172 - multimeter
173 Information provided by serial multimeters, such as the `Metex
174 M-4650CR'.
176 - mysql
177 MySQL server statistics: Commands issued, handlers triggered, thread
178 usage, query cache utilization and traffic/octets sent and received.
180 - netapp
181 Plugin to query performance values from a NetApp storage system using the
182 “Manage ONTAP” SDK provided by NetApp.
184 - netlink
185 Very detailed Linux network interface and routing statistics. You can get
186 (detailed) information on interfaces, qdiscs, classes, and, if you can
187 make use of it, filters.
189 - network
190 Receive values that were collected by other hosts. Large setups will
191 want to collect the data on one dedicated machine, and this is the
192 plugin of choice for that.
194 - nfs
195 NFS Procedures: Which NFS command were called how often. Only NFSv2 and
196 NFSv3 right now.
198 - nginx
199 Collects statistics from `nginx' (speak: engine X), a HTTP and mail
200 server/proxy.
202 - ntpd
203 NTP daemon statistics: Local clock drift, offset to peers, etc.
205 - nut
206 Network UPS tools: UPS current, voltage, power, charge, utilisation,
207 temperature, etc. See upsd(8).
209 - numa
210 Information about Non-Uniform Memory Access (NUMA).
212 - olsrd
213 Queries routing information from the “Optimized Link State Routing”
214 daemon.
216 - onewire (EXPERIMENTAL!)
217 Read onewire sensors using the owcapu library of the owfs project.
218 Please read in collectd.conf(5) why this plugin is experimental.
220 - openvpn
221 RX and TX of each client in openvpn-status.log (status-version 2).
222 <http://openvpn.net/index.php/documentation/howto.html>
224 - oracle
225 Query data from an Oracle database.
227 - perl
228 The perl plugin implements a Perl-interpreter into collectd. You can
229 write your own plugins in Perl and return arbitrary values using this
230 API. See collectd-perl(5).
232 - pf
233 Query statistics from BSD's packet filter "pf".
235 - pinba
236 Receive and dispatch timing values from Pinba, a profiling extension for
237 PHP.
239 - ping
240 Network latency: Time to reach the default gateway or another given
241 host.
243 - postgresql
244 PostgreSQL database statistics: active server connections, transaction
245 numbers, block IO, table row manipulations.
247 - powerdns
248 PowerDNS name server statistics.
250 - processes
251 Process counts: Number of running, sleeping, zombie, ... processes.
253 - protocols
254 Counts various aspects of network protocols such as IP, TCP, UDP, etc.
256 - python
257 The python plugin implements a Python interpreter into collectd. This
258 makes it possible to write plugins in Python which are executed by
259 collectd without the need to start a heavy interpreter every interval.
260 See collectd-python(5) for details.
262 - redis
263 The redis plugin gathers information from a redis server, including:
264 uptime, used memory, total connections etc.
266 - routeros
267 Query interface and wireless registration statistics from RouterOS.
269 - rrdcached
270 RRDtool caching daemon (RRDcacheD) statistics.
272 - sensors
273 System sensors, accessed using lm_sensors: Voltages, temperatures and
274 fan rotation speeds.
276 - serial
277 RX and TX of serial interfaces. Linux only; needs root privileges.
279 - snmp
280 Read values from SNMP (Simple Network Management Protocol) enabled
281 network devices such as switches, routers, thermometers, rack monitoring
282 servers, etc. See collectd-snmp(5).
284 - swap
285 Pages swapped out onto harddisk or whatever is called `swap' by the OS..
287 - table
288 Parse table-like structured files.
290 - tail
291 Follows (tails) logfiles, parses them by lines and submits matched
292 values.
294 - tail_csv
295 Follows (tails) files in CSV format, parses each line and submits
296 extracted values.
298 - tape
299 Bytes and operations read and written on tape devices. Solaris only.
301 - tcpconns
302 Number of TCP connections to specific local and remote ports.
304 - teamspeak2
305 TeamSpeak2 server statistics.
307 - ted
308 Plugin to read values from `The Energy Detective' (TED).
310 - thermal
311 Linux ACPI thermal zone information.
313 - tokyotyrant
314 Reads the number of records and file size from a running Tokyo Tyrant
315 server.
317 - uptime
318 System uptime statistics.
320 - users
321 Users currently logged in.
323 - varnish
324 Various statistics from Varnish, an HTTP accelerator.
326 - vmem
327 Virtual memory statistics, e. g. the number of page-ins/-outs or the
328 number of pagefaults.
330 - vserver
331 System resources used by Linux VServers.
332 See <http://linux-vserver.org/>.
334 - wireless
335 Link quality of wireless cards. Linux only.
337 - xmms
338 Bitrate and frequency of music played with XMMS.
340 - zfs_arc
341 Statistics for ZFS' “Adaptive Replacement Cache” (ARC).
343 * Output can be written or sent to various destinations by the following
344 plugins:
346 - amqp
347 Sends JSON-encoded data to an Advanced Message Queuing Protocol (AMQP)
348 server, such as RabbitMQ.
350 - csv
351 Write to comma separated values (CSV) files. This needs lots of
352 diskspace but is extremely portable and can be analysed with almost
353 every program that can analyse anything. Even Microsoft's Excel..
355 - network
356 Send the data to a remote host to save the data somehow. This is useful
357 for large setups where the data should be saved by a dedicated machine.
359 - perl
360 Of course the values are propagated to plugins written in Perl, too, so
361 you can easily do weird stuff with the plugins we didn't dare think of
362 ;) See collectd-perl(5).
364 - python
365 It's possible to implement write plugins in Python using the python
366 plugin. See collectd-python(5) for details.
368 - rrdcached
369 Output to round-robin-database (RRD) files using the RRDtool caching
370 daemon (RRDcacheD) - see rrdcached(1). That daemon provides a general
371 implementation of the caching done by the `rrdtool' plugin.
373 - rrdtool
374 Output to round-robin-database (RRD) files using librrd. See rrdtool(1).
375 This is likely the most popular destination for such values. Since
376 updates to RRD-files are somewhat expensive this plugin can cache
377 updates to the files and write a bunch of updates at once, which lessens
378 system load a lot.
380 - unixsock
381 One can query the values from the unixsock plugin whenever they're
382 needed. Please read collectd-unixsock(5) for a description on how that's
383 done.
385 - write_graphite
386 Sends data to Carbon, the storage layer of Graphite.
388 - write_http
389 Sends the values collected by collectd to a web-server using HTTP POST
390 requests. The transmitted data is either in a form understood by the
391 Exec plugin or formatted in JSON.
393 - write_mongodb
394 Sends data to MongoDB, a NoSQL database.
396 - write_redis
397 Sends the values to a Redis key-value database server.
399 - write_riemann
400 Sends data to Riemann, a stream processing and monitoring system.
402 * Logging is, as everything in collectd, provided by plugins. The following
403 plugins keep up informed about what's going on:
405 - logfile
406 Writes logmessages to a file or STDOUT/STDERR.
408 - perl
409 Log messages are propagated to plugins written in Perl as well.
410 See collectd-perl(5).
412 - python
413 It's possible to implement log plugins in Python using the python plugin.
414 See collectd-python(5) for details.
416 - syslog
417 Logs to the standard UNIX logging mechanism, syslog.
419 * Notifications can be handled by the following plugins:
421 - notify_desktop
422 Send a desktop notification to a notification daemon, as defined in
423 the Desktop Notification Specification. To actually display the
424 notifications, notification-daemon is required.
425 See http://www.galago-project.org/specs/notification/.
427 - notify_email
428 Send an E-mail with the notification message to the configured
429 recipients.
431 - exec
432 Execute a program or script to handle the notification.
433 See collectd-exec(5).
435 - logfile
436 Writes the notification message to a file or STDOUT/STDERR.
438 - network
439 Send the notification to a remote host to handle it somehow.
441 - perl
442 Notifications are propagated to plugins written in Perl as well.
443 See collectd-perl(5).
445 - python
446 It's possible to implement notification plugins in Python using the
447 python plugin. See collectd-python(5) for details.
449 * Value processing can be controlled using the "filter chain" infrastructure
450 and "matches" and "targets". The following plugins are available:
452 - match_empty_counter
453 Match counter values which are currently zero.
455 - match_hashed
456 Match values using a hash function of the hostname.
458 - match_regex
459 Match values by their identifier based on regular expressions.
461 - match_timediff
462 Match values with an invalid timestamp.
464 - match_value
465 Select values by their data sources' values.
467 - target_notification
468 Create and dispatch a notification.
470 - target_replace
471 Replace parts of an identifier using regular expressions.
473 - target_scale
474 Scale (multiply) values by an arbitrary value.
476 - target_set
477 Set (overwrite) entire parts of an identifier.
479 * Miscellaneous plugins:
481 - aggregation
482 Selects multiple value lists based on patterns or regular expressions
483 and creates new aggregated values lists from those.
485 - threshold
486 Checks values against configured thresholds and creates notifications if
487 values are out of bounds. See collectd-threshold(5) for details.
489 - uuid
490 Sets the hostname to an unique identifier. This is meant for setups
491 where each client may migrate to another physical host, possibly going
492 through one or more name changes in the process.
494 * Performance: Since collectd is running as a daemon it doesn't spend much
495 time starting up again and again. With the exception of the exec plugin no
496 processes are forked. Caching in output plugins, such as the rrdtool and
497 network plugins, makes sure your resources are used efficiently. Also,
498 since collectd is programmed multithreaded it benefits from hyperthreading
499 and multicore processors and makes sure that the daemon isn't idle if only
500 one plugin waits for an IO-operation to complete.
502 * Once set up, hardly any maintenance is necessary. Setup is kept as easy
503 as possible and the default values should be okay for most users.
506 Operation
507 ---------
509 * collectd's configuration file can be found at `sysconfdir'/collectd.conf.
510 Run `collectd -h' for a list of builtin defaults. See `collectd.conf(5)'
511 for a list of options and a syntax description.
513 * When the `csv' or `rrdtool' plugins are loaded they'll write the values to
514 files. The usual place for these files is beneath `/var/lib/collectd'.
516 * When using some of the plugins, collectd needs to run as user root, since
517 only root can do certain things, such as craft ICMP packages needed to ping
518 other hosts. collectd should NOT be installed setuid root since it can be
519 used to overwrite valuable files!
521 * Sample scripts to generate graphs reside in `contrib/' in the source
522 package or somewhere near `/usr/share/doc/collectd' in most distributions.
523 Please be aware that those script are meant as a starting point for your
524 own experiments.. Some of them require the `RRDs' Perl module.
525 (`librrds-perl' on Debian) If you have written a more sophisticated
526 solution please share it with us.
528 * The RRAs of the automatically created RRD files depend on the `step'
529 and `heartbeat' settings given. If change these settings you may need to
530 re-create the files, losing all data. Please be aware of that when changing
531 the values and read the rrdtool(1) manpage thoroughly.
534 collectd and chkrootkit
535 -----------------------
537 If you are using the `dns' plugin chkrootkit(1) will report collectd as a
538 packet sniffer ("<iface>: PACKET SNIFFER(/usr/sbin/collectd[<pid>])"). The
539 plugin captures all UDP packets on port 53 to analyze the DNS traffic. In
540 this case, collectd is a legitimate sniffer and the report should be
541 considered to be a false positive. However, you might want to check that
542 this really is collectd and not some other, illegitimate sniffer.
545 Prerequisites
546 -------------
548 To compile collectd from source you will need:
550 * Usual suspects: C compiler, linker, preprocessor, make, ...
552 * A POSIX-threads (pthread) implementation.
553 Since gathering some statistics is slow (network connections, slow devices,
554 etc) the collectd is parallelized. The POSIX threads interface is being
555 used and should be found in various implementations for hopefully all
556 platforms.
558 * CoreFoundation.framework and IOKit.framework (optional)
559 For compiling on Darwin in general and the `apple_sensors' plugin in
560 particular.
561 <http://developer.apple.com/corefoundation/>
563 * libclntsh (optional)
564 Used by the `oracle' plugin.
566 * libcredis (optional)
567 Used by the redis plugin. Please note that you require a 0.2.2 version
568 or higher. <http://code.google.com/p/credis/>
570 * libcurl (optional)
571 If you want to use the `apache', `ascent', `curl', `nginx', or `write_http'
572 plugin.
573 <http://curl.haxx.se/>
575 * libdbi (optional)
576 Used by the `dbi' plugin to connect to various databases.
577 <http://libdbi.sourceforge.net/>
579 * libesmtp (optional)
580 For the `notify_email' plugin.
581 <http://www.stafford.uklinux.net/libesmtp/>
583 * libganglia (optional)
584 Used by the `gmond' plugin to process data received from Ganglia.
585 <http://ganglia.info/>
587 * libgcrypt (optional)
588 Used by the `network' plugin for encryption and authentication.
589 <http://www.gnupg.org/>
591 * libhal (optional)
592 If present, the uuid plugin will check for UUID from HAL.
593 <http://hal.freedesktop.org/>
595 * libiptc (optional)
596 For querying iptables counters.
597 <http://netfilter.org/>
599 If not found on the system, a version shipped with this distribution can
600 be used. It requires some Linux headers in /usr/include/linux. You can
601 force the build system to use the shipped version by specifying
602 --with-libiptc=shipped
603 when running the configure script.
605 * libjvm (optional)
606 Library that encapsulates the `Java Virtual Machine' (JVM). This library is
607 used by the Java plugin to execute Java bytecode. See “Configuring with
608 libjvm” below.
609 <http://openjdk.java.net/> (and others)
611 * libmemcached (optional)
612 Used by the `memcachec' plugin to connect to a memcache daemon.
613 <http://tangent.org/552/libmemcached.html>
615 * libmodbus (optional)
616 Used by the “modbus” plugin to communicate with Modbus/TCP devices. The
617 “modbus” plugin works with version 2.0.3 of the library – due to frequent
618 API changes other versions may or may not compile cleanly.
619 <http://www.libmodbus.org/>
621 * libmysqlclient (optional)
622 Unsurprisingly used by the `mysql' plugin.
623 <http://dev.mysql.com/>
625 * libnetapp (optional)
626 Required for the “netapp” plugin.
627 This library is part of the “Manage ONTAP SDK” published by NetApp.
629 * libnetlink (optional)
630 Used, obviously, for the `netlink' plugin.
631 <http://www.linuxfoundation.org/en/Net:Iproute2>
633 * libnetsnmp (optional)
634 For the `snmp' plugin.
635 <http://www.net-snmp.org/>
637 * libnotify (optional)
638 For the `notify_desktop' plugin.
639 <http://www.galago-project.org/>
641 * liboping (optional)
642 Used by the `ping' plugin to send and receive ICMP packets.
643 <http://verplant.org/liboping/>
645 * libowcapi (optional)
646 Used by the `onewire' plugin to read values from onewire sensors (or the
647 owserver(1) daemon).
648 <http://www.owfs.org/>
650 * libpcap (optional)
651 Used to capture packets by the `dns' plugin.
652 <http://www.tcpdump.org/>
654 * libperfstat (optional)
655 Used by various plugins to gather statistics under AIX.
657 * libperl (optional)
658 Obviously used by the `perl' plugin. The library has to be compiled with
659 ithread support (introduced in Perl 5.6.0).
660 <http://www.perl.org/>
662 * libpq (optional)
663 The PostgreSQL C client library used by the `postgresql' plugin.
664 <http://www.postgresql.org/>
666 * libprotobuf-c, protoc-c (optional)
667 Used by the `pinba' plugin to generate a parser for the network packets
668 sent by the Pinba PHP extension.
669 <http://code.google.com/p/protobuf-c/>
671 * libpython (optional)
672 Used by the `python' plugin. Currently, Python 2.3 and later and Python 3
673 are supported.
674 <http://www.python.org/>
676 * librabbitmq (optional; also called “rabbitmq-c”)
677 Used by the AMQP plugin for AMQP connections, for example to RabbitMQ.
678 <http://hg.rabbitmq.com/rabbitmq-c/>
680 * librouteros (optional)
681 Used by the `routeros' plugin to connect to a device running `RouterOS'.
682 <http://verplant.org/librouteros/>
684 * librrd (optional)
685 Used by the `rrdtool' and `rrdcached' plugins. The latter requires RRDtool
686 client support which was added after version 1.3 of RRDtool. Versions 1.0,
687 1.2 and 1.3 are known to work with the `rrdtool' plugin.
688 <http://oss.oetiker.ch/rrdtool/>
690 * librt, libsocket, libkstat, libdevinfo (optional)
691 Various standard Solaris libraries which provide system functions.
692 <http://developers.sun.com/solaris/>
694 * libsensors (optional)
695 To read from `lm_sensors', see the `sensors' plugin.
696 <http://www.lm-sensors.org/>
698 * libstatgrab (optional)
699 Used by various plugins to collect statistics on systems other than Linux
700 and/or Solaris.
701 <http://www.i-scream.org/libstatgrab/>
703 * libtokyotyrant (optional)
704 Used by the tokyotyrant plugin.
705 <http://1978th.net/tokyotyrant/>
707 * libupsclient/nut (optional)
708 For the `nut' plugin which queries nut's `upsd'.
709 <http://networkupstools.org/>
711 * libvirt (optional)
712 Collect statistics from virtual machines.
713 <http://libvirt.org/>
715 * libxml2 (optional)
716 Parse XML data. This is needed for the `ascent' and `libvirt' plugins.
717 <http://xmlsoft.org/>
719 * libxmms (optional)
720 <http://www.xmms.org/>
722 * libyajl (optional)
723 Parse JSON data. This is needed for the `curl_json' plugin.
724 <http://github.com/lloyd/yajl>
726 * libvarnish (optional)
727 Fetches statistics from a Varnish instance. This is needed for the Varnish plugin
728 <http://varnish-cache.org>
730 Configuring / Compiling / Installing
731 ------------------------------------
733 To configure, build and install collectd with the default settings, run
734 `./configure && make && make install'. For detailed, generic instructions
735 see INSTALL. For a complete list of configure options and their description,
736 run `./configure --help'.
738 By default, the configure script will check for all build dependencies and
739 disable all plugins whose requirements cannot be fulfilled (any other plugin
740 will be enabled). To enable a plugin, install missing dependencies (see
741 section `Prerequisites' above) and rerun `configure'. If you specify the
742 `--enable-<plugin>' configure option, the script will fail if the depen-
743 dencies for the specified plugin are not met. In that case you can force the
744 plugin to be built using the `--enable-<plugin>=force' configure option.
745 This will most likely fail though unless you're working in a very unusual
746 setup and you really know what you're doing. If you specify the
747 `--disable-<plugin>' configure option, the plugin will not be built. If you
748 specify the `--enable-all-plugins' or `--disable-all-plugins' configure
749 options, all plugins will be enabled or disabled respectively by default.
750 Explicitly enabling or disabling a plugin overwrites the default for the
751 specified plugin. These options are meant for package maintainers and should
752 not be used in everyday situations.
754 By default, collectd will be installed into `/opt/collectd'. You can adjust
755 this setting by specifying the `--prefix' configure option - see INSTALL for
756 details. If you pass DESTDIR=<path> to `make install', <path> will be
757 prefixed to all installation directories. This might be useful when creating
758 packages for collectd.
760 Configuring with libjvm
761 -----------------------
763 To determine the location of the required files of a Java installation is not
764 an easy task, because the locations vary with your kernel (Linux, SunOS, …)
765 and with your architecture (x86, SPARC, …) and there is no ‘java-config’
766 script we could use. Configuration of the JVM library is therefore a bit
767 tricky.
769 The easiest way to use the `--with-java=$JAVA_HOME' option, where
770 `$JAVA_HOME' is usually something like:
771 /usr/lib/jvm/java-1.5.0-sun-1.5.0.14
773 The configure script will then use find(1) to look for the following files:
775 - jni.h
776 - jni_md.h
777 - libjvm.so
779 If found, appropriate CPP-flags and LD-flags are set and the following
780 library checks succeed.
782 If this doesn't work for you, you have the possibility to specify CPP-flags,
783 C-flags and LD-flags for the ‘Java’ plugin by hand, using the following three
784 (environment) variables:
786 - JAVA_CPPFLAGS
787 - JAVA_CFLAGS
788 - JAVA_LDFLAGS
790 For example (shortened for demonstration purposes):
792 ./configure JAVA_CPPFLAGS="-I$JAVA_HOME/include -I$JAVA_HOME/include/linux"
794 Adding "-ljvm" to the JAVA_LDFLAGS is done automatically, you don't have to
795 do that.
797 Crosscompiling
798 --------------
800 To compile correctly collectd needs to be able to initialize static
801 variables to NAN (Not A Number). Some C libraries, especially the GNU
802 libc, have a problem with that.
804 Luckily, with GCC it's possible to work around that problem: One can define
805 NAN as being (0.0 / 0.0) and `isnan' as `f != f'. However, to test this
806 ``implementation'' the configure script needs to compile and run a short
807 test program. Obviously running a test program when doing a cross-
808 compilation is, well, challenging.
810 If you run into this problem, you can use the `--with-nan-emulation'
811 configure option to force the use of this implementation. We can't promise
812 that the compiled binary actually behaves as it should, but since NANs
813 are likely never passed to the libm you have a good chance to be lucky.
815 Likewise, collectd needs to know the layout of doubles in memory, in order
816 to craft uniform network packets over different architectures. For this, it
817 needs to know how to convert doubles into the memory layout used by x86. The
818 configure script tries to figure this out by compiling and running a few
819 small test programs. This is of course not possible when cross-compiling.
820 You can use the `--with-fp-layout' option to tell the configure script which
821 conversion method to assume. Valid arguments are:
823 * `nothing' (12345678 -> 12345678)
824 * `endianflip' (12345678 -> 87654321)
825 * `intswap' (12345678 -> 56781234)
828 Contact
829 -------
831 For questions, bug reports, development information and basically all other
832 concerns please send an email to collectd's mailing list at
833 <collectd at verplant.org>.
835 For live discussion and more personal contact visit us in IRC, we're in
836 channel #collectd on freenode.
839 Author
840 ------
842 Florian octo Forster <octo at verplant.org>,
843 Sebastian tokkee Harl <sh at tokkee.org>,
844 and many contributors (see `AUTHORS').
846 Please send bug reports and patches to the mailing list, see `Contact'
847 above.