165 lines
4.4 KiB
Groff
165 lines
4.4 KiB
Groff
'\"macro stdmacro
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.TH DKSTAT 1
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.SH NAME
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\f3dkstat\f1 \- report disk I/O statistics
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.SH SYNOPSIS
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\f3dkstat\f1
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[\f3\-h\f1 \f2host\f1]
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[\f3\-L\f1]
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[\f3\-f\f1 {\f3r\f1|\f3t\f1|\f3s\f1}]
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[\f3\-r\f1] [\f3\-w\f1]
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[\f3\-n\f1 \f2ndisks\f1]
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[\f3\-c\f1]
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[\f3\-a\f1] [\f3\-i\f1 \f2devspec\f1[\f3\|,\|\f1\f2devspec\f1 ...]]
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[\f3\-x\f1 \f2devspec\f1[\f3\|,\|\f1\f2devspec\f1 ...]]
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[\f2interval\f1 [\f2repeat\f1]]
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.SH "TYPICAL USAGE"
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To monitor I/O rates on all disks every 5 seconds
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.sp
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.in +1i
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.ftCW
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dkstat
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.in
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.ft1
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.PP
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To continuously display a table of disks on the host "babylon",
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use the following command;
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.sp
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.in +1i
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.ftCW
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dkstat \-c \-ft \-h babylon
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.in
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.ft1
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.SH DESCRIPTION
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.B dkstat
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reports physical disk I/O statistics.
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The default report shows the average physical I/O rate (requests per second, or
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IOPS)
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to each disk during the sample
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.I interval
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(default 5 seconds).
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.PP
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The options to
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.I dkstat
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are as follows;
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.PP
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.TP 5
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\f3\-?\f1
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Output usage information.
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.TP 5
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\f3\-h\f1 \f2host\f1
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Report for the host \f2host\f1, which must be running
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.BR pmcd (1).
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The default is to report for the local host.
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.TP 5
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\f3\-L\f1
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Report for the local host and by-pass
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.BR pmcd (1).
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This option is mutually exclusive with the \f3\-h\f1 option
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and is the default if
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.BR pmcd (1)
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is not running.
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.TP
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\f3\-c\f1
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Invokes continuous mode, using a
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.BR curses (3)
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display. This is most useful with the
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"sorted" (\f3\-fs\f1) and "table" (\f3\-ft\f1) display
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formats.
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.TP 5
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\f3\-f\f1 {\f3r\f1|\f3t\f1|\f3s\f1}
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Selects the report format as follows:
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.RS
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.TP 5
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\f3\-f\f1\f3r\f1
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selects ``row'' format (one column per drive).
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The report is sorted on drive name across the page.
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This is the default display format.
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.TP 5
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\f3\-f\f1\f3t\f1
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selects ``table'' format (one line per controller).
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The report is sorted on controller name down the page
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and by drive unit number across the page.
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.sp0.5v
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For SCSI devices with non-zero Logical Unit Numbers (LUNs) all devices
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for a single SCSI target address appear in a the same row, sorted
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by LUN.
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Down the page, rows are sorted by SCSI target within controller.
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.TP 5
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\f3\-f\f1\f3s\f1
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selects ``sorted'' format (one drive per line).
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The report is sorted for the most active drive, depending on the \f3\-r\f1
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and \f3\-w\f1 flags.
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If neither \f3\-r\f1 or \f3\-w\f1 are given,
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the report is sorted on total number of I/Os (reads plus writes).
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The \f3\-n\f1 option restricts the report to the
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.I ndisks
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most active disks (default 22).
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The \f3%Busy\f1 column in the output
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is the percentage of time during the interval
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that the drive was active.
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The \f3MeanST\f1 column in the output
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is the average service time of all requests which
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completed during the interval (in units of milliseconds).
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.RE
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.TP 5
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\f3\-r\f1
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Only report reads from each drive.
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The default is to sum reads and writes.
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The \f3\-f\f1\f3s\f1 style report will be sorted
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for the drives which perform the most read I/Os per second.
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.TP
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\f3\-w\f1
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Only report writes to each drive.
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The \f3\-f\f1\f3s\f1 style report will be sorted
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for the drives which perform the most write I/Os per second.
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.TP
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\f3\-rw\f1
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Report both reads and writes to each drive.
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If neither \f3\-r\f1 or \f3\-w\f1 are given, then report
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total I/Os (reads plus writes).
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.TP
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\f2interval\f1 [\f2repeats\f1]
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Specifies the interval in seconds between successive reports
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(default 5 seconds) and the number of intervals to report
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(default is to repeat forever).
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All statistics are averaged over the interval.
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.SH "DEVICE SELECTION"
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The \f3\-a\f1 flag (default) causes all drives and controllers
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to be reported (depending on the report format).
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This may be modified by the \f3\-i\f1 option to include only some drives
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and exclude all others, or by the \f3\-x\f1 option to exclude some drives
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and include all others.
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.PP
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The argument to the \f3\-i\f1 or \f3\-x\f1 option is a comma separated list
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(without spaces before or after each comma)
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of device specifiers (\f2devspec\f1).
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A \f2devspec\f1 is a string of characters that might reasonably be expected
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to be the prefix for the names (as report via \f3\-I\f1) of one or more
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devices.
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.PP
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Examples;
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.TP 15
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\f3dks1d6l3\f1
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SCSI controller 1, target 6, LUN 3.
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.TP 15
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\f3dks0d1\f1
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SCSI controller 0, target 1, all LUNs.
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.TP 15
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\f3dks4\f1
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All drives on SCSI controller 4.
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.TP 15
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\f3dks6,dks0d3\f1
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All drives on SCSI controller 6
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and SCSI target 3 on SCSI controller 0.
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.TP
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.SH FILES
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.SH SEE ALSO
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\f3pmcd\f1(1),
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\f3sar\f1(1),
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\f3sadc\f1(1),
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\f3gr_top\f1(1),
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\f3osview\f1(1)
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and
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\f3gr_osview\f1(1).
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