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Интерактивная система просмотра системных руководств (man-ов)

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iostat (8)
  • iostat (1) ( Solaris man: Команды и прикладные программы пользовательского уровня )
  • iostat (1) ( Linux man: Команды и прикладные программы пользовательского уровня )
  • >> iostat (8) ( FreeBSD man: Команды системного администрирования )

  • BSD mandoc
     

    NAME

    
    
    iostat
    
     - report
    
    I/O
    
    statistics
     
    

    SYNOPSIS

    [-CdhIKoTxz? ] [-c count ] [-M core ] [-n devs ] [-N system ] [-t type , if , pass ] [-w wait ] [drives ]  

    DESCRIPTION

    The utility displays kernel I/O statistics on terminal, device and cpu operations. The first statistics that are printed are averaged over the system uptime. To get information about the current activity, a suitable wait time should be specified, so that the subsequent sets of printed statistics will be averaged over that time.

    The options are as follows:

    -c
    Repeat the display count times. If no wait interval is specified, the default is 1 second.
    -C
    Display CPU statistics. This is on by default, unless -d is specified.
    -d
    Display only device statistics. If this flag is turned on, only device statistics will be displayed, unless -C or -T is also specified to enable the display of CPU or TTY statistics.
    -h
    Put in `top' mode. In this mode, will show devices in order from highest to lowest bytes per measurement cycle.
    -I
    Display total statistics for a given time period, rather than average statistics for each second during that time period.
    -K
    In the blocks transferred display (-o), display block count in kilobytes rather then the device native block size.
    -M
    Extract values associated with the name list from the specified core instead of the default ``/dev/kmem ''
    -n
    Display up to devs number of devices. The utility will display fewer devices if there are not devs devices present.
    -N
    Extract the name list from the specified system instead of the default ``/boot/kernel/kernel ''
    -o
    Display old-style device statistics. Sectors per second, transfers per second, and milliseconds per seek are displayed. If -I is specified, total blocks/sectors, total transfers, and milliseconds per seek are displayed.
    -t
    Specify which types of devices to display. There are three different categories of devices:

    device type:

    da
    Direct Access devices
    sa
    Sequential Access devices
    printer
    Printers
    proc
    Processor devices
    worm
    Write Once Read Multiple devices
    cd
    CD devices
    scanner
    Scanner devices
    optical
    Optical Memory devices
    changer
    Medium Changer devices
    comm
    Communication devices
    array
    Storage Array devices
    enclosure
    Enclosure Services devices
    floppy
    Floppy devices

    interface:

    IDE
    Integrated Drive Electronics devices
    SCSI
    Small Computer System Interface devices
    other
    Any other device interface

    passthrough:

    pass
    Passthrough devices

    The user must specify at least one device type, and may specify at most one device type from each category. Multiple device types in a single device type statement must be separated by commas.

    Any number of -t arguments may be specified on the command line. All -t arguments are ORed together to form a matching expression against which all devices in the system are compared. Any device that fully matches any -t argument will be included in the output, up to the number of devices that can be displayed in 80 columns, or the maximum number of devices specified by the user.

    -T
    Display TTY statistics. This is on by default, unless -d is specified.
    -w
    Pause wait seconds between each display. If no repeat count is specified, the default is infinity.
    -x
    Show extended disk statistics. Each disk is displayed on a line of its own with all available statistics.
    -z
    If -x is specified, omit lines for devices with no activity.
    -?
    Display a usage statement and exit.

    The utility displays its information in the following format:

    tty

    tin
    characters read from terminals
    tout
    characters written to terminals

    devices
    Device operations. The header of the field is the device name and unit number. The utility will display as many devices as will fit in a standard 80 column screen, or the maximum number of devices in the system, whichever is smaller. If -n is specified on the command line, will display the smaller of the requested number of devices, and the maximum number of devices in the system. To force to display specific drives, their names may be supplied on the command line. The utility will not display more devices than will fit in an 80 column screen, unless the -n argument is given on the command line to specify a maximum number of devices to display. If fewer devices are specified on the command line than will fit in an 80 column screen, will show only the specified devices.

    The standard device display shows the following statistics:

    KB/t
    kilobytes per transfer
    tps
    transfers per second
    MB/s
    megabytes per second

    The standard device display, with the -I flag specified, shows the following statistics:

    KB/t
    kilobytes per transfer
    xfrs
    total number of transfers
    MB
    total number of megabytes transferred

    The extended device display, with the -x flag specified, shows the following statistics:

    r/s
    read operations per second
    w/s
    write operations per second
    kr/s
    kilobytes read per second
    kw/s
    kilobytes write per second
    wait
    transactions queue length
    svc_t
    average duration of transactions, in milliseconds
    %b
    % of time the device had one or more outstanding transactions

    The old-style display (using -o shows the following statistics:

    sps
    sectors transferred per second
    tps
    transfers per second
    msps
    average milliseconds per transaction

    The old-style display, with the -I flag specified, shows the following statistics:

    blk
    total blocks/sectors transferred
    xfr
    total transfers
    msps
    average milliseconds per transaction

    cpu

    us
    % of cpu time in user mode
    ni
    % of cpu time in user mode running niced processes
    sy
    % of cpu time in system mode
    in
    % of cpu time in interrupt mode
    id
    % of cpu time in idle mode

     

    FILES

    /boot/kernel/kernel
    Default kernel namelist.
    /dev/kmem
    Default memory file.

     

    EXAMPLES

    iostat -w 1 da0 da1 cd0

    Display statistics for the first two Direct Access devices and the first CDROM device every second ad infinitum.

    iostat -c 2

    Display the statistics for the first four devices in the system twice, with a one second display interval.

    iostat -t da -t cd -w 1

    Display statistics for all CDROM and Direct Access devices every second ad infinitum.

    iostat -t da,scsi,pass -t cd,scsi,pass

    Display statistics once for all SCSI passthrough devices that provide access to either Direct Access or CDROM devices.

    iostat -h -n 8 -w 1

    Display up to 8 devices with the most I/O every second ad infinitum.

    iostat -dh -t da -w 1

    Omit the TTY and CPU displays, show devices in order of performance and show only Direct Access devices every second ad infinitum.

    iostat -Iw 3

    Display total statistics every three seconds ad infinitum.

    iostat -odICTw 2 -c 9

    Display total statistics using the old-style output format 9 times, with a two second interval between each measurement/display. The -d flag generally disables the TTY and CPU displays, but since the -T and -C flags are given, the TTY and CPU displays will be displayed.  

    SEE ALSO

    fstat(1), netstat(1), nfsstat(1), ps(1), systat(1), devstat(3), gstat(8), pstat(8), vmstat(8)

    The sections starting with ``Interpreting system activity'' in "Installing and Operating 4.3BSD" .  

    HISTORY

    This version of first appeared in Fx 3.0 .  

    AUTHORS

    An Kenneth Merry Aq ken@FreeBSD.org  

    BUGS

    The use of as a debugging tool for crash dumps is probably limited because there is currently no way to get statistics that only cover the time immediately before the crash.


     

    Index

    NAME
    SYNOPSIS
    DESCRIPTION
    FILES
    EXAMPLES
    SEE ALSO
    HISTORY
    AUTHORS
    BUGS


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