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Iostat
iostat (''input/output statistics'') is a computer system monitor tool used to collect and show operating system computer data storage, storage input and output statistics. It is often used to identify performance issues with storage devices, including local Disk storage, disks, or remote disks accessed over network file systems such as Network File System, NFS. It can also be used to provide information about Computer terminal, terminal (TTY) input and output, and also includes some basic CPU information. Syntax and availability iostat -x displays output where each line (row) gives numerical data for one device. The first column lists the device name, and subsequent columns show various statistics for that device. Columns include the average service time (''svc_t'', which includes not only the time a request is in the service queue, but also the seek time and transfer time), the average busy percentage (''%b'', essentially the proportion of time that the device is in use), and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sysstat
sysstat (''system statistics'') is a collection of performance monitoring tools for Linux. It is available on Unix and Unix-like operating systems An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for .... Software included in sysstat package: * * * * * * * * * References See also * sar (Unix) Utility software {{Computing-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sar (Unix)
System Activity Report (sar) is a Unix System V-derived system monitor command used to report on various system loads, including CPU activity, memory/paging, interrupts, device load, network and swap space utilization. Sar uses /proc filesystem for gathering information. Platform support Sar was originally developed for the Unix System V operating system; it is available in AIX, HP-UX, Solaris and other System V based operating systems but it is not available for macOS or FreeBSD. Prior to 2013 there was a bsdsar tool, but it is now deprecated. Most Linux distributions provide sar utility through the sysstat package. Syntax sar flags -e time -f filename i sec -s time ; : filename Uses filename as the data source for sar. The default is the current daily data file /var/adm/sa/sadd. ; : time Selects data up to time. The default is 18:00. ; : sec Selects data at intervals as close as possible to sec seconds. Example ser@localhost sar # Displays current CPU act ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Systat (tool)
systat is a BSD UNIX console application for displaying system statistics in fullscreen mode using ncurses/curses. It is available on, and by default ships in the base systems of, FreeBSD, NetBSD, OpenBSD and DragonFly BSD. It was first released as part of 4.3BSD in . Both internally and in the interface of the user the utility consists of several distinct modules and tabs, referred to as "displays" in FreeBSD, NetBSD and DragonFly, and "views" in OpenBSD, which are automatically refreshed every specified number of seconds. These modules cover all system components, including statistics resembling vmstat, iostat and netstat in all of the BSDs, as well as pf and sensors views in some of the BSDs. The systat utility is notably absent from OS X, where a GUI-based Activity Monitor performs similar functions. See also * vmstat * iostat * top * netstat In computing, netstat is a command-line network utility that displays open network sockets, routing tables, and a numb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System Monitor
A system monitor is a hardware or software component used to monitor system resources and performance in a computer system. Among the management issues regarding use of system monitoring tools are resource usage and privacy. Monitoring can track both input and output values and events of systems. Overview Software monitors occur more commonly, sometimes as a part of a widget engine. These monitoring systems are often used to keep track of system resources, such as CPU usage and frequency, or the amount of free RAM. They are also used to display items such as free space on one or more hard drives, the temperature of the CPU and other important components, and networking information including the system IP address and current rates of upload and download. Other possible displays may include the date and time, system uptime, computer name, username, hard drive S.M.A.R.T. data, fan speeds, and the voltages being provided by the power supply. Less common are hardware-based sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mpstat
mpstat is a computer command-line software used in Unix-type operating systems to report (on the screen) processor-related statistics. It is used in computer monitoring in order to diagnose problems or to build statistics about a computer's CPU usage. Description The mpstat command writes to standard output activities for each available processor. The mpstat command can be used both on SMP and UP machines, but in the latter, only global average activities will be printed. Usage $ mpstat Interval is the time in seconds between printing out a line of statistics. Count is the number of lines of output you want. Note that the first line of output from mpstat (like iostat, vmstat, etc.) contains averages since system boot. The subsequent lines will show current values. Examples Different examples of output under different operating systems: under Linux kernel 4.14 on a two CPU machine: Linux 4.14.24.mptcp (hostname) 05/23/2018 _x86_64_ (2 CPU) 03:51:19 PM CPU ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix-like
A Unix-like (sometimes referred to as UN*X, *nix or *NIX) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-like Application software, application is one that behaves like the corresponding List of POSIX commands, Unix command or Unix shell, shell. Although there are general Unix philosophy, philosophies for Unix design, there is no technical standard defining the term, and opinions can differ about the degree to which a particular operating system or application is Unix-like. Some well-known examples of Unix-like operating systems include Linux, FreeBSD and OpenBSD. These systems are often used on servers as well as on personal computers and other devices. Many popular applications, such as the Apache HTTP Server, Apache web server and the Bash (Unix shell), Bash shell, are also designed to be used on Unix-like systems. Definition The Open ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix
Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others. Initially intended for use inside the Bell System, AT&T licensed Unix to outside parties in the late 1970s, leading to a variety of both academic and commercial Unix variants from vendors including University of California, Berkeley ( BSD), Microsoft (Xenix), Sun Microsystems ( SunOS/ Solaris), HP/ HPE ( HP-UX), and IBM ( AIX). The early versions of Unix—which are retrospectively referred to as " Research Unix"—ran on computers such as the PDP-11 and VAX; Unix was commonly used on minicomputers and mainframes from the 1970s onwards. It distinguished itself from its predecessors as the first portable operating system: almost the entire operating system is written in the C programming language (in 1973), which allows U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AT&T Bell Laboratories
Nokia Bell Labs, commonly referred to as ''Bell Labs'', is an American industrial research and development company owned by Finnish technology company Nokia. With headquarters located in Murray Hill, New Jersey, Murray Hill, New Jersey, the company operates several laboratories in the United States and around the world. As a former subsidiary of the American Telephone and Telegraph Company (AT&T), Bell Labs and its researchers have been credited with the development of radio astronomy, the transistor, the laser, the photovoltaic cell, the charge-coupled device (CCD), information theory, the Unix operating system, and the programming languages B (programming language), B, C (programming language), C, C++, S (programming language), S, SNOBOL, AWK, AMPL, and others, throughout the 20th century. Eleven Nobel Prizes and five Turing Awards have been awarded for work completed at Bell Laboratories. Bell Labs had its origin in the complex corporate organization of the Bell System telepho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Netstat
In computing, netstat is a command-line network utility that displays open network sockets, routing tables, and a number of network interface (network interface controller or software-defined network interface) and network protocol statistics. It is available on Unix, Plan 9, Inferno, and Unix-like operating systems including macOS, Linux, Solaris and BSD. It is also available on IBM OS/2 and on Microsoft Windows NT-based operating systems including Windows XP, Windows Vista, Windows 7, Windows 8 and Windows 10. It is used for finding problems in the network and to determine the amount of traffic on the network as a performance measurement. On Linux this program is mostly obsolete, although still included in many distributions. On Linux, netstat (part of "net-tools") is superseded by ss (part of iproute2). The replacement for netstat -r is ip route, the replacement for netstat -i is ip -s link, and the replacement for netstat -g is ip maddr, all of which are recommen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disk-drive Performance Characteristics
Higher performance in hard disk drives comes from devices which have better performance characteristics. These performance characteristics can be grouped into two categories: access time and data transfer time (or rate). Access time The ''access time'' or ''response time'' of a rotating drive is a measure of the time it takes before the drive can actually transfer data. The factors that control this time on a rotating drive are mostly related to the mechanical nature of the rotating disks and moving heads. It is composed of a few independently measurable elements that are added together to get a single value when evaluating the performance of a storage device. The access time can vary significantly, so it is typically provided by manufacturers or measured in benchmarks as an average. The key components that are typically added together to obtain the access time are: * Seek time * Rotational latency * Command processing time * Settle time Seek time With rotating drives, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Device Mapper
The device mapper is a framework provided by the Linux kernel for mapping physical block devices onto higher-level ''virtual block devices''. It forms the foundation of the logical volume manager (LVM), software RAIDs and dm-crypt disk encryption, and offers additional features such as file system snapshots. Device mapper works by passing data from a virtual block device, which is provided by the device mapper itself, to another block device. Data can be also modified in transition, which is performed, for example, in the case of device mapper providing disk encryption or simulation of unreliable hardware behavior. This article focuses on the device mapper implementation in the Linux kernel, but the device mapper functionality is also available in both NetBSD and DragonFly BSD. Usage Applications (like LVM2 and Enterprise Volume Management System (EVMS)) that need to create new mapped devices talk to the device mapper via the libdevmapper.so shared library, which in tur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
