1PCP-IOSTAT(1)               General Commands Manual              PCP-IOSTAT(1)
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NAME

6       pmiostat, pcp-iostat - report block I/O statistics
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SYNOPSIS

9       pcp [pcp options] iostat [-u?]  [-G method] [-P precision] [-R pattern]
10       [-x [dm][,t][,h][,noidle]]
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DESCRIPTION

13       pcp-iostat reports I/O statistics for SCSI (by default)  or  other  de‐
14       vices (if the -x option is specified).
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OPTIONS

17       When  invoked  via  the  pcp(1)  command,  the  pcp options -A/--align,
18       -a/--archive,   -h/--host,   -O/--origin,   -S/--start,   -s/--samples,
19       -T/--finish,    -t/--interval,    -v/--version,    -Z/--timezone    and
20       -z/--hostzone become indirectly available; refer to PCPIntro(1)  for  a
21       complete description of these options.
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23       The additional command line options available for pcp-iostat are:
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25       -G method, --aggregate=method
26            Specifies  that  statistics  for device names matching the regular
27            expression specified with the -R regex option should be aggregated
28            according  to  method.  Note this is aggregation based on matching
29            device names (not temporal aggregation).  When -G is used, the de‐
30            vice  name column is reported as method(regex), e.g.  if -G sum -R
31            'sd(a|b)$' is specified, the device column will  be  sum(sd(a|b)$)
32            and  summed statistics for sda and sdb will be reported in the re‐
33            maining columns.  If -G is specified but -R is not specified, then
34            the default regex is .*, i.e. matching all device names.  If meth‐
35            od is sum then the statistics are summed.  This includes the %util
36            column,  which  may  therefore exceed 100% if more than one device
37            name matches.  If method is avg then the statistics are summed and
38            then  averaged by dividing by the number of matching device names.
39            If method is min or max, the minimum  or  maximum  statistics  for
40            matching devices are reported, respectively.
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42       -P N, --precision=N
43            This indicates the precision (number of decimal places) to report.
44            The default precision N may be set to something other than the de‐
45            fault  (2).  Note that the avgrq-sz and avgqu-sz fields are always
46            reported with N+1 decimals of precision.  These  fields  typically
47            have values less than 1.
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49       -R pattern, --regex=pattern
50            This  restricts  the report to device names matching a regular ex‐
51            pression pattern.  The given pattern is searched as a  perl  style
52            regular  expression,  and will match any portion of a device name.
53            e.g. '^sd[a-zA-Z]+' will match all device names starting with 'sd'
54            followed  by  one or more alphabetic characters.  e.g. '^sd(a|b)$'
55            will only match 'sda' and 'sdb'.  e.g. 'sda$' will match 'sda' but
56            not 'sdab'.  See also the -G option for aggregation options.
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58       -u, --no-interpolation
59            When  replaying  a set of archives, by default values are reported
60            according to the requested sample interval (-t  option),  not  ac‐
61            cording  to the actual interval recorded in the archive(s).  With‐
62            out this option PCP interpolates the values to be  reported  based
63            on  the records in the set of archives, which is particularly use‐
64            ful when the -t option is used to replay a set of archives with  a
65            longer  sampling  interval than that with which the archive(s) was
66            originally recorded with.  With the -u option, uninterpolated  re‐
67            porting  is enabled - every value is reported according to the na‐
68            tive recording interval in the set of archives.  When the  -u  op‐
69            tion  is specified, the -t option makes no sense and is incompati‐
70            ble because the replay interval is always the same as the  record‐
71            ing  interval  in  the set of archive.  In addition, -u only makes
72            sense when replaying archives, see the -a option  on  PCPIntro(1),
73            and so if -u is specified then -a must also be specified.
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75       -V, --version
76            Display version number and exit.
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78       -x comma-separated-options
79            Specifies a comma-separated list of one or more extended reporting
80            options as follows:
81            dm - report statistics for device-mapper logical  devices  instead
82            of SCSI devices,
83            t  -  prefix every line in the report with a timestamp in ctime(3)
84            format,
85            h - omit the heading, which is otherwise reported  every  24  sam‐
86            ples,
87            noidle - Do not display statistics for idle devices.
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89       -?, --help
90            Display usage message and exit.
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REPORT

93       The columns in the pcp-iostat report have the following interpretation:
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95       Timestamp
96              When  the -x t option is specified, this column is the timestamp
97              in ctime(3) format.
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99       Device Specifies the scsi device name, or if -x dm  is  specified,  the
100              device-mapper  logical  device name.  When -G is specified, this
101              is replaced by the aggregation method and regular  expression  -
102              see the -G and -R options above.
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104       rrqm/s The  number of read requests expressed as a rate per-second that
105              were merged during the reporting interval by the I/O scheduler.
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107       wrqm/s The number of write requests expressed as a rate per-second that
108              were merged during the reporting interval by the I/O scheduler.
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110       r/s    The  number  of  read  requests  completed  by the device (after
111              merges), expressed as a rate per second during the reporting in‐
112              terval.
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114       w/s    The  number  of  write  requests  completed by the device (after
115              merges), expressed as a rate per second during the reporting in‐
116              terval.
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118       rkB/s  The  average  volume  of  data read from the device expressed as
119              KBytes/second during the reporting interval.
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121       wkB/s  The average volume of data written to the  device  expressed  as
122              KBytes/second during the reporting interval.
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124       avgrq-sz
125              The  average  I/O  request size for both reads and writes to the
126              device expressed as Kbytes during the reporting interval.
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128       avgqu-sz
129              The average queue length of read and write requests to  the  de‐
130              vice during the reporting interval.
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132       await  The  average  time  in milliseconds that read and write requests
133              were queued (and serviced) to the device  during  the  reporting
134              interval.
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136       r_await
137              The  average time in milliseconds that read requests were queued
138              (and serviced) to the device during the reporting interval.
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140       w_await
141              The average time in milliseconds that write requests were queued
142              (and serviced) to the device during the reporting interval.
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144       %util  The  percentage  of  time during the reporting interval that the
145              device was busy processing requests.  A value of 100%  indicates
146              device saturation.
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PCP ENVIRONMENT

149       Environment variables with the prefix PCP_ are used to parameterize the
150       file and directory names used by PCP.  On each installation,  the  file
151       /etc/pcp.conf  contains  the  local  values  for  these variables.  The
152       $PCP_CONF variable may be used to specify an alternative  configuration
153       file, as described in pcp.conf(5).
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155       For environment variables affecting PCP tools, see pmGetOptions(3).
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SEE ALSO

158       PCPIntro(1),  pcp(1),  iostat2pcp(1), pmcd(1), pmchart(1), pmlogger(1),
159       pcp.conf(5) and pcp.env(5).
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163Performance Co-Pilot                  PCP                        PCP-IOSTAT(1)
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