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

90       The   columns   in   the   pcp-tapestat   report   have  the  following
91       interpretation:
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93       Timestamp
94              When the -x t option is specified, this column is the  timestamp
95              in ctime(3) format.
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97       Device Specifies  the  tape device name.  When -G is specified, this is
98              replaced by the aggregation method and regular expression -  see
99              the -G and -R options above.
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101       r/s    The  number  of  reads issued expressed as the number per second
102              averaged over the interval.
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104       w/s    The number of writes issued expressed as the number  per  second
105              averaged over the interval.
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107       kb_r/s The  amount  of  data  read  expressed  in  kilobytes per second
108              averaged over the interval.
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110       kb_w/s The amount of data written expressed  in  kilobytes  per  second
111              averaged over the interval.
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113       r_pct  Read  percentage wait - the percentage of time over the interval
114              spent waiting for  read  requests  to  complete.   The  time  is
115              measured  from  when  the request is dispatched to the SCSI mid-
116              layer until it signals that it completed.
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118       w_pct  Write percentage wait - the percentage of time over the interval
119              spent  waiting  for  write  requests  to  complete.  The time is
120              measured from when the request is dispatched to  the  SCSI  mid-
121              layer until it signals that it completed.
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123       o_pct  Overall  percentage  wait  -  the  percentage  of  time over the
124              interval spent waiting for any I/O request  to  complete  (read,
125              write, and other).
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127       Rs/s   The  number of I/Os, expressed as the number per second averaged
128              over  the  interval,  where  a  non-zero  residual   value   was
129              encountered.
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131       o_cnt  The  number of I/Os, expressed as the number per second averaged
132              over the interval, that were included  as  "other".   Other  I/O
133              includes  ioctl  calls  made  to  the  tape  driver and implicit
134              operations performed by the tape driver such as rewind on  close
135              (for  tape devices that implement rewind on close).  It does not
136              include any I/O performed using  methods  outside  of  the  tape
137              driver (e.g. via sg ioctls).
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PCP ENVIRONMENT

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

149       PCPIntro(1),  pcp(1), pmcd(1), pmchart(1), pmlogger(1), pcp.conf(5) and
150       pcp.env(5).
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154Performance Co-Pilot                  PCP                      PCP-TAPESTAT(1)
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