- Source: Netdata
- Source: NETDATA
Netdata is a partially
open source tool designed to collect real-time metrics, such as CPU usage, disk activity, bandwidth usage, website visits, etc., and then display them in live, easy-to-interpret charts.
Overview
Netdata consists of a daemon that, when executed, is responsible for collecting and displaying information in real-time.
It is mostly written in C, Python and JavaScript, and aims to use minimal system resources.
It can be run on any Linux system to monitor any system or application, and is capable of running on PCs, servers, and embedded Linux devices.
Features
Netdata is designed to be installed on a system without interrupting any of the applications running on it. It operates according to the memory requirements specified by the user, using only idle CPU cycles. Once the application begins, it will not perform disk I/O beyond logging. The tool saves to disk at the end of its execution and reloads at startup.
By default it contains certain plugins that collect key system metrics, but its behavior is extensible by using its plugin API.
Graphics generated by Netdata can be embedded into web pages. It has an interface with customizable themes and can be manually configured by the user with HTML.
There are no dependencies, as it operates as its own web server, with static web files.
Starting with v1.12, Netdata collects anonymous usage information by default and sends it to Google Analytics, a feature which can be disabled via manual configuration.
Operation
When executing the daemon on Linux using the netdata command, threads are generated that collect information from each resource, using internal and/or external plugins. In turn, it keeps a record of the values collected in memory (without doing any Disk I/O).
It operates as a stand-alone web server for its own static files, necessary for the representation of
its dashboards. It provides a REST API so that the browser can access the information.
Each installation of the application works autonomously. Although different running instances of the application can be saved to one dashboard, every Netdata instance is independent. Only the browser can connect all installations of different systems, unifying graphics from different sources as if they came from the same server.
Development
Netdata is currently maintained by nearly 400 contributors, all helping (at various levels) to serve the thousands of individual users and businesses who utilize this tool.
The user with the most contributions is currently Costa Tsaousis, the CEO and Founder of Netdata, with over 600,000 additions to the code. The second most-active user is Ilya Mashchenko.
The all-time most popular addition to Netdata appears to be adding support for data collection from Vnstat, a pull request by Noah Troy with nearly 200 individual comments (more than any other pull request).
The all-time most popular feature request appears to be adding support for running multiple freeipmi jobs from the same Netdata.
See also
Comparison of dashboard software
Comparison of network monitoring systems
References
External links
netdata on GitHub
NETDATA is a file format used primarily for data transfer and storage on IBM mainframe systems, although implementations are available for other systems.
Description
NETDATA files are 80-byte card image files containing unloaded file data plus metadata to allow the original file to be reconstituted on the receiving system. A complete NETDATA file consists of a number of control records, followed by data records and terminated by a trailer record. All records have the same format:
A one-byte length field containing the length of a logical segment of the file. A segment has a maximum length of 255 bytes. With the length and flags a segment can contain up to 253 bytes of data.
A one-byte flags field describing this segment:
X'80' - this is the first segment of a record
X'40' - this is the last segment of a record. If the record requires only one segment the flags will contain X'C0'
X'20' - this segment is part of a control record
X'10' - this segment contains the record number of the next record
X'0F' - reserved
= Control records
=Control records have a six-character EBCDIC identifier in bytes 2-7 following the length and flags. They contain a number of self-defining fields, called text units. Each text unit consists of a two byte text unit key identifying this text unit, a two-byte big-endian binary number of length-data pairs that follow for this key (usually one), a two byte length field identifying the length of the text unit data, and a text unit of the specified length. Implementations are expected to ignore any text unit information not relevant to the receiving system.
Header Control Record
The header record must be the first record of a NETDATA file. It has the identifier "INMR01". It contains information identifying the sender: node (host), timestamp, and user id, the length of the control record segments, and the target (receiving) node and user id. It may optionally contain a request for acknowledgement of receipt, the version number of the data format, the number of files in the transmission, and a "user parameter string." CMS allows only one file per transmission, but TSO/E and other systems may allow more than one.
File Utility Control Record
This record describes how the file's data is to be reconstituted. Its identifier is "INMR02". Bytes 8-11 contain the big-endian binary number of the file to which this record applies. If there are multiple files in a transmission they are numbered starting with one. The rest of this record describes the file's format, and one or more steps ("utility programs") which must be executed in order to rebuild this file. The text units identify the file's organization (INMDSORG: sequential, partitioned, etc.), its fixed of maximum record length (INMLRECL), its record format (INMRECFM: fixed, variable, etc) the approximate size of the file (IBMSIZE), and the utility program name(s) (INMUTILN). It may also contain the file's block size, creation date, number of directory blocks, name, expiration date, file mode number, last change date, last reference date, member name list (for partitioned datasets), a note file, and a user parameter string.
Data Control Record
The Data Control Record immediately precedes the data and describes its format, similar to the Utility Control Record. Its identifier is "INMR03". This record is ignored by CMS, but is used by TSO/E. It contains the file's organization (INMDSORG), its record length (INMLRECL), its record format (INMRECFM), and the file size (IBMSIZE).
User Control Record
The User Control record can appear at any point in the data stream. Its identifier is "INMR04". If present it is ignored by CMS, but may be used by other systems. It contains only a User Parameter String (INMUSERP).
Trailer Control Record
This record marks the end of the file. Its identifier is "INMR06". No other data is defined for this record.
Acknowledgement Control Record
This record has an id of "INMR07". It is used by the receiving system to acknowledge receipt of a transmission. It contains one of the text units File Name (INMDSNM) or Note File (INMTERM) plus, optionally, the Origin Time Stamp (INMFTIME).
A note file (sometimes called a "PROFS note") "is a short communication, the kind usually done by letter.".
= Data records
=Data records (identified by their flag value), follow the Data Control Record, if present, and precede the Trailer Control Record. Records can be any size up to INMLRECL. They are sent as multiple segments of up to 253 bytes, split into 80 byte records for transmission, and reassembled by the receiver. Settings of the flags byte in each record mark the beginning, end, or a complete record of the file. Bytes of a record can contain any bit pattern. No character values are reserved.
References
External links
Netdatax - NETDATA command for Linux
