collectd - System information collection daemon
=================================================
http://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
Using digital barometer sensor MPL115A2 or MPL3115 from Freescale
provides absolute barometric pressure, air pressure reduced to sea level
and temperature.
- 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.
- cgroups
CPU accounting information for process groups under Linux.
- 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)
- 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.
- 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).
- filecount
Count the number of files in directories.
- fscache
Linux file-system based caching framework statistics.
- gmond
Receive multicast traffic from Ganglia instances.
- hddtemp
Hard disk temperatures using hddtempd.
- interface
Interface traffic: Number of octets, packets and errors for each
interface.
- iptables
Iptables' counters: Number of bytes that were matched by a certain
iptables rule.
- ipmi
IPMI (Intelligent Platform Management Interface) sensors information.
- 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 “Configuring with libjvm” below.
- 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.
- 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).
- 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.
<http://www.danga.com/memcached/>
- 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. Only NFSv2 and
NFSv3 right now.
- 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.
- nut
Network UPS tools: UPS current, voltage, power, charge, utilisation,
temperature, etc. See upsd(8).
- numa
Information about Non-Uniform Memory Access (NUMA).
- 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).
<http://openvpn.net/index.php/documentation/howto.html>
- oracle
Query data from an Oracle database.
- 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.
- 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 <http://linux-vserver.org/>.
- wireless
Link quality of wireless cards. Linux only.
- xmms
Bitrate and frequency of music played with XMMS.
- zfs_arc
Statistics for ZFS' “Adaptive Replacement Cache” (ARC).
- 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..
- 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.
- 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_tsdb
Sends data OpenTSDB, a scalable no master, no shared state time series
database.
- 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_mongodb
Sends data to MongoDB, a NoSQL database.
- write_redis
Sends the values to a Redis key-value database server.
- write_riemann
Sends data to Riemann, a stream processing and monitoring system.
* Logging is, as everything in collectd, provided by plugins. The following
plugins keep up 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.
- 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 ("<iface>: PACKET SNIFFER(/usr/sbin/collectd[<pid>])"). 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, ...
* 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.
* 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.
<https://github.com/lynix/aerotools-ng>
* CoreFoundation.framework and IOKit.framework (optional)
For compiling on Darwin in general and the `apple_sensors' plugin in
particular.
<http://developer.apple.com/corefoundation/>
* libatasmart (optional)
Used by the `smart' plugin.
<http://git.0pointer.de/?p=libatasmart.git>
* 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. <https://github.com/redis/hiredis>
* libcurl (optional)
If you want to use the `apache', `ascent', `bind', `curl', `curl_json',
`curl_xml', `nginx', or `write_http' plugin.
<http://curl.haxx.se/>
* libdbi (optional)
Used by the `dbi' plugin to connect to various databases.
<http://libdbi.sourceforge.net/>
* libesmtp (optional)
For the `notify_email' plugin.
<http://www.stafford.uklinux.net/libesmtp/>
* libganglia (optional)
Used by the `gmond' plugin to process data received from Ganglia.
<http://ganglia.info/>
* libgcrypt (optional)
Used by the `network' plugin for encryption and authentication.
<http://www.gnupg.org/>
* libhal (optional)
If present, the `uuid' plugin will check for UUID from HAL.
<http://hal.freedesktop.org/>
* 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.
<http://netfilter.org/>
* libjvm (optional)
Library that encapsulates the `Java Virtual Machine' (JVM). This library is
used by the `java' plugin to execute Java bytecode. See “Configuring with
libjvm” below.
<http://openjdk.java.net/> (and others)
* libldap (optional)
Used by the `openldap' plugin.
<http://www.openldap.org/>
* liblvm2 (optional)
Used by the `lvm' plugin.
<ftp://sources.redhat.com/pub/lvm2/>
* libmemcached (optional)
Used by the `memcachec' plugin to connect to a memcache daemon.
<http://tangent.org/552/libmemcached.html>
* libmnl (optional)
Used by the `netlink' plugin.
<http://www.netfilter.org/projects/libmnl/>
* 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.
<http://www.libmodbus.org/>
* libmysqlclient (optional)
Unsurprisingly used by the `mysql' plugin.
<http://dev.mysql.com/>
* libnetapp (optional)
Required for the `netapp' plugin.
This library is part of the “Manage ONTAP SDK” published by NetApp.
* libnetsnmp (optional)
For the `snmp' plugin.
<http://www.net-snmp.org/>
* libnotify (optional)
For the `notify_desktop' plugin.
<http://www.galago-project.org/>
* libopenipmi (optional)
Used by the `ipmi' plugin to prove IPMI devices.
<http://openipmi.sourceforge.net/>
* liboping (optional)
Used by the `ping' plugin to send and receive ICMP packets.
<http://octo.it/liboping/>
* libowcapi (optional)
Used by the `onewire' plugin to read values from onewire sensors (or the
owserver(1) daemon).
<http://www.owfs.org/>
* libpcap (optional)
Used to capture packets by the `dns' plugin.
<http://www.tcpdump.org/>
* 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).
<http://www.perl.org/>
* libpq (optional)
The PostgreSQL C client library used by the `postgresql' plugin.
<http://www.postgresql.org/>
* libprotobuf-c, protoc-c (optional)
Used by the `pinba' plugin to generate a parser for the network packets
sent by the Pinba PHP extension, and by the `write_riemann' plugin to
generate events to be sent to a Riemann server.
<http://code.google.com/p/protobuf-c/>
* libpython (optional)
Used by the `python' plugin. Currently, Python 2.3 and later and Python 3
are supported.
<http://www.python.org/>
* librabbitmq (optional; also called “rabbitmq-c”)
Used by the `amqp' plugin for AMQP connections, for example to RabbitMQ.
<http://hg.rabbitmq.com/rabbitmq-c/>
* librdkafka (optional; also called “rdkafka”)
Used by the `write_kafka' plugin for producing messages and sending them
to a Kafka broker.
<https://github.com/edenhill/librdkafka>
* librouteros (optional)
Used by the `routeros' plugin to connect to a device running `RouterOS'.
<http://octo.it/librouteros/>
* 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.
<http://oss.oetiker.ch/rrdtool/>
* librt, libsocket, libkstat, libdevinfo (optional)
Various standard Solaris libraries which provide system functions.
<http://developers.sun.com/solaris/>
* libsensors (optional)
To read from `lm_sensors', see the `sensors' plugin.
<http://www.lm-sensors.org/>
* 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.
<http://www.i-scream.org/libstatgrab/>
* libtokyotyrant (optional)
Used by the `tokyotyrant' plugin.
<http://1978th.net/tokyotyrant/>
* libupsclient/nut (optional)
For the `nut' plugin which queries nut's `upsd'.
<http://networkupstools.org/>
* libvirt (optional)
Collect statistics from virtual machines.
<http://libvirt.org/>
* libxml2 (optional)
Parse XML data. This is needed for the `ascent', `bind', `curl_xml' and
`virt' plugins.
<http://xmlsoft.org/>
* libxmms (optional)
<http://www.xmms.org/>
* libyajl (optional)
Parse JSON data. This is needed for the `curl_json' and `log_logstash'
plugins.
<http://github.com/lloyd/yajl>
* libvarnish (optional)
Fetches statistics from a Varnish instance. This is needed for the
`varnish' plugin.
<http://varnish-cache.org>
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-<plugin>' 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-<plugin>=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-<plugin>' 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=<path> to `make install', <path> will be
prefixed to all installation directories. This might be useful when creating
packages for collectd.
Configuring with libjvm
-----------------------
To determine the location of the required files of a Java installation is not
an easy task, because the locations vary with your kernel (Linux, SunOS, …)
and with your architecture (x86, SPARC, …) and there is no ‘java-config’
script we could use. Configuration of the JVM library is therefore a bit
tricky.
The easiest way to use the `--with-java=$JAVA_HOME' option, where
`$JAVA_HOME' is usually something like:
/usr/lib/jvm/java-1.5.0-sun-1.5.0.14
The configure script will then use find(1) to look for the following files:
- jni.h
- jni_md.h
- libjvm.so
If found, appropriate CPP-flags and LD-flags are set and the following
library checks succeed.
If this doesn't work for you, you have the possibility to specify CPP-flags,
C-flags and LD-flags for the ‘Java’ plugin by hand, using the following three
(environment) variables:
- JAVA_CPPFLAGS
- JAVA_CFLAGS
- JAVA_LDFLAGS
For example (shortened for demonstration purposes):
./configure JAVA_CPPFLAGS="-I$JAVA_HOME/include -I$JAVA_HOME/include/linux"
Adding "-ljvm" to the JAVA_LDFLAGS is done automatically, you don't have to
do that.
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
- automke
- flex
- bison
- libtool
- libtool-ltdl
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
-------
For questions, bug reports, development information and basically all other
concerns please send an email to collectd's mailing list at
<list at collectd.org>.
For live discussion and more personal contact visit us in IRC, we're in
channel #collectd on freenode.
Author
------
Florian octo Forster <octo at collectd.org>,
Sebastian tokkee Harl <sh at tokkee.org>,
and many contributors (see `AUTHORS').
Please send bug reports and patches to the mailing list, see `Contact'
above.