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

6       pcp-tapestat - report tape I/O statistics
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SYNOPSIS

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

13       pcp-tapestat reports I/O statistics for tape devices.
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OPTIONS

16       When invoked via  the  pcp(1)  command,  the  -a/--archive,  -h/--host,
17       -O/--origin,  -s/--samples,  -t/--interval,  -Z/--timezone  and several
18       other pcp options become indirectly available; refer to PCPIntro(1) for
19       a complete description of these options.
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21       The additional command line options available for pcp-tapestat are:
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23       -G method, --aggregate=method
24            Specifies  that  statistics  for device names matching the regular
25            expression specified with the -R regex option should be aggregated
26            according  to  method.  Note this is aggregation based on matching
27            device names (not temporal aggregation).  When  -G  is  used,  the
28            device  name  column is reported as method(regex), e.g.  if -G sum
29            -R  'st(0|1)$'  is  specified,   the   device   column   will   be
30            sum(st(0|1)$)  and  summed  statistics  for  st0  and  st1 will be
31            reported in the remaining columns.  If -G is specified but  -R  is
32            not  specified,  then  the  default regex is .*, i.e. matching all
33            device names.  If method is sum then the  statistics  are  summed.
34            If  method is avg then the statistics are summed and then averaged
35            by dividing by the number of matching device names.  If method  is
36            min or max, the minimum or maximum statistics for matching devices
37            are reported, respectively.
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39       -P N, --precision=N
40            This indicates the precision (number of decimal places) to report.
41            The  default  precision  N  may be set to something other than the
42            default (2).  Note that  the  avgrq-sz  and  avgqu-sz  fields  are
43            always reported with N+1 decimals of precision.  These fields typ‐
44            ically have values less than 1.
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46       -R pattern, --regex=pattern
47            This restricts the report  to  device  names  matching  a  regular
48            expression pattern.  The given pattern is searched as a perl style
49            regular expression, and will match any portion of a  device  name.
50            e.g.  '^st[0-9]+'  will  match all device names starting with 'st'
51            followed by one or more numbers.  e.g. '^st(0|1)$' will only match
52            'st0' and 'st1'.  e.g. 'st0$' will match 'st0' but not 'st1'.  See
53            also the -G option for aggregation options.
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55       -u, --no-interpolation
56            When replaying a set of archives, by default values  are  reported
57            according  to  the  requested  sample  interval  (-t  option), not
58            according to the  actual  interval  recorded  in  the  archive(s).
59            Without  this  option  PCP  interpolates the values to be reported
60            based on the records in the set of archives, which is particularly
61            useful when the -t option is used to replay a set of archives with
62            a longer sampling interval than that with which the archive(s) was
63            originally  recorded  with.   With  the  -u option, uninterpolated
64            reporting is enabled - every value is reported  according  to  the
65            native  recording  interval  in  the set of archives.  When the -u
66            option is specified, the -t option makes no sense and is incompat‐
67            ible because the replay interval is always the same as the record‐
68            ing interval in the set of archive.  In addition,  -u  only  makes
69            sense  when  replaying archives, see the -a option on PCPIntro(1),
70            and so if -u is specified then -a must also be specified.
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72       -x comma-separated-options
73            Specifies a comma-separated list of one or more extended reporting
74            options as follows:
75            t  -  prefix every line in the report with a timestamp in ctime(3)
76            format,
77            h - omit the heading, which is otherwise reported  every  24  sam‐
78            ples,
79            noidle - Do not display statistics for idle devices.
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REPORT

82       The  columns  in the pcp-tapestat report have the following interpreta‐
83       tion:
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85       Timestamp
86              When the -x t option is specified, this column is the  timestamp
87              in ctime(3) format.
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89       Device Specifies  the  tape device name.  When -G is specified, this is
90              replaced by the aggregation method and regular expression -  see
91              the -G and -R options above.
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93       r/s    The  number  of  reads issued expressed as the number per second
94              averaged over the interval.
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96       w/s    The number of writes issued expressed as the number  per  second
97              averaged over the interval.
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99       kb_r/s The  amount of data read expressed in kilobytes per second aver‐
100              aged over the interval.
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102       kb_w/s The amount of data written expressed  in  kilobytes  per  second
103              averaged over the interval.
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105       r_pct  Read  percentage wait - the percentage of time over the interval
106              spent waiting for read requests to complete.  The time  is  mea‐
107              sured  from when the request is dispatched to the SCSI mid-layer
108              until it signals that it completed.
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110       w_pct  Write percentage wait - the percentage of time over the interval
111              spent  waiting for write requests to complete.  The time is mea‐
112              sured from when the request is dispatched to the SCSI  mid-layer
113              until it signals that it completed.
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115       o_pct  Overall percentage wait - the percentage of time over the inter‐
116              val spent waiting for any I/O request to complete (read,  write,
117              and other).
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119       Rs/s   The  number of I/Os, expressed as the number per second averaged
120              over the interval, where a non-zero residual value  was  encoun‐
121              tered.
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123       o_cnt  The  number of I/Os, expressed as the number per second averaged
124              over the interval, that were included  as  "other".   Other  I/O
125              includes ioctl calls made to the tape driver and implicit opera‐
126              tions performed by the tape driver such as rewind on close  (for
127              tape  devices  that  implement  rewind  on  close).  It does not
128              include any I/O performed using  methods  outside  of  the  tape
129              driver (e.g. via sg ioctls).
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DIAGNOSTICS

132       All  are  generated  on  standard  error  and  are intended to be self-
133       explanatory.
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PCP ENVIRONMENT

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

145       PCPIntro(1), pcp(1), pmcd(1), pmchart(1), pmlogger(1), pcp.conf(5)  and
146       pcp.env(5).
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150Performance Co-Pilot                  PCP                      PCP-TAPESTAT(1)
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