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sar




SYNOPSIS

       sar [ -A ] [ -b ] [ -B ] [ -c ] [ -d ] [ -H ] [ -h ] [  -i
       interval  ] [ -q ] [ -r ] [ -R ] [ -t ] [ -u ] [ -v ] [ -V
       ] [ -w ] [ -W ] [ -y ] [ -n { DEV | EDEV | SOCK | FULL } ]
       [  -x { pid | SELF | SUM | ALL } ] [ -X { pid | SELF | ALL
       } ] [ -I { irq | SUM | PROC | ALL | XALL } ] [ -U { cpu  |
       ALL  }  ]  [  -o  [  filename ] | -f [ filename ] ] [ -s [
       hh:mm:ss ] ] [ -e [ hh:mm:ss ] ] [ interval [ count ] ]


DESCRIPTION

       The sar command writes to standard output the contents  of
       selected  cumulative  activity  counters  in the operating
       system. The accounting system, based on the values in  the
       count  and  interval  parameters,  writes  information the
       specified number of times spaced at the  specified  inter­
       vals  in  seconds.   If  the  interval parameter is set to
       zero, the sar command displays the average statistics  for
       the  time  since the system was started. The default value
       for the count parameter is 1. If its value is set to zero,
       then  reports  are  generated continuously.  The collected
       data can also be saved in the file  specified  by  the  -o
       filename  flag,  in  addition  to being displayed onto the
       screen. If filename is omitted, sar uses the standard sys­
       tem  activity  daily data file, the /var/log/sa/sadd file,
       where the dd parameter indicates the current day.

       The sar command extracts and  writes  to  standard  output
       records  previously  saved  in  a  file.  This file can be
       either the one specified by the -f flag  or,  by  default,
       the standard system activity daily data file.

       You  can  select information about specific system activi­
       ties using flags. Not specifying any  flags  selects  only
       CPU  activity.   Specifying  the  -A flag is equivalent to
       specifying -bBcdqrRuvwWy -I SUM -I PROC -n FULL -U ALL.

       The default version of the sar  command  (CPU  utilization
       report) might be one of the first facilities the user runs
       to begin system activity investigation, because  it  moni­
       tors  major  system  resources. If CPU utilization is near
       100 percent (user + nice + system), the  workload  sampled
       is CPU-bound.

       If  multiple  samples and multiple reports are desired, it
       is convenient to specify an output file for the  sar  com­
       mand.   Run  the  sar command as a background process. The
       syntax for this is:

       sar -o data.file interval count >/dev/null 2>&1 &

       All data is captured in binary form and saved  to  a  file
              SUM -I PROC -n FULL -U ALL.

       -b     Report  I/O  and transfer rate statistics. The fol­
              lowing values are displayed:

              tps
                     Total number of transfers  per  second  that
                     were  issued to the physical disk.  A trans­
                     fer is an I/O request to the physical  disk.
                     Multiple  logical  requests  can be combined
                     into a single I/O request to  the  disk.   A
                     transfer is of indeterminate size.

              rtps
                     Total  number  of  read  requests per second
                     issued to the physical disk.

              wtps
                     Total number of write  requests  per  second
                     issued to the physical disk.

              bread/s
                     Total  amount of data read from the drive in
                     blocks per second.  Blocks are equivalent to
                     sectors  with post 2.4 kernels and therefore
                     have a size of 512 bytes.  With  older  ker­
                     nels, a block is of indeterminate size.

              bwrtn/s
                     Total amount of data written to the drive in
                     blocks per second.

       -B     Report paging statistics. The following values  are
              displayed:

              pgpgin/s
                     Total  number  of blocks the system paged in
                     from disk per second.

              pgpgout/s
                     Total number of blocks the system paged  out
                     to disk per second.

              activepg
                     Number of active (recently touched) pages in
                     memory.  Note that a page has a size of 4 kB
                     or  8  kB according to the machine architec­
                     ture.

              inadtypg
                     Number of inactive dirty (modified or poten­
                     tially modified) pages in memory.

              proc/s
                     Total number of processes created  per  sec­
                     ond.

       -d     Report  activity for each block device (kernels 2.4
              and later only). When data is displayed, the device
              specification  dev m-n is generally used ( DEV col­
              umn).  m is the major number of the device, whereas
              n is a distinctive number.

              tps
                     Indicate  the number of transfers per second
                     that were issued to  the  device.   Multiple
                     logical requests can be combined into a sin­
                     gle I/O request to the device. A transfer is
                     of indeterminate size.

              sect/s
                     Number of sectors transferred from or to the
                     device. The size of a sector is 512 bytes.

       -e hh:mm:ss
              Set the ending time of the report. The default end­
              ing  time  is  18:00:00.  Hours  must  be  given in
              24-hour format.  This option can be used only  when
              data are read from or written to a file (options -f
              or -o ).

       -f filename
              Extract records from filename (created  by  the  -o
              filename  flag).  The default value of the filename
              parameter is  the  current  daily  data  file,  the
              /var/log/sa/sadd  file.  The -f option is exclusive
              of the -o option.

       -h     When  reading data from a file, print its  contents
              in  a  format that can easily be handled by pattern
              processing commands like awk.  The output  consists
              of  fields separated by a tab. Each record contains
              the hostname of the host where  sar  was  run,  the
              interval  value  (or  -1  if  not  applicable), the
              timestamp (UTC value - Coordinated Universal  Time)
              in seconds from the epoch, the device name (or - if
              not applicable), the field name and its value.

       -H     When  reading data from a file, print its  contents
              in  a format that can easily be ingested by a rela­
              tional database  system.  The  output  consists  of
              fields  separated  by a semicolon. Each record con­
              tains the hostname of the host where sar  was  run,
              the  interval  value (or -1 if not applicable), the
              sar timestamp in a form easily acceptable  by  most
              that the total number of  interrupts  received  per
              second  is  to  be displayed. The ALL keyword indi­
              cates that statistics from the first 16  interrupts
              are  to be reported, whereas the XALL keyword indi­
              cates that statistics from all interrupts,  includ­
              ing  potential  APIC  interrupt  sources, are to be
              reported.  Last, if you use the PROC  keyword,  the
              number  of  interrupts  per second received by each
              processor is displayed.

       -n DEV | EDEV | SOCK | FULL
              Report network statistics.

              With the DEV keyword, statistics from  the  network
              devices  are  reported.   The  following values are
              displayed:

              IFACE
                     Name of  the  network  interface  for  which
                     statistics are reported.

              rxpck/s
                     Total number of packets received per second.

              txpck/s
                     Total number of packets transmitted per sec­
                     ond.

              rxbyt/s
                     Total number of bytes received per second.

              txbyt/s
                     Total  number  of bytes transmitted per sec­
                     ond.

              rxcmp/s
                     Number of compressed  packets  received  per
                     second (for cslip etc.).

              txcmp/s
                     Number of compressed packets transmitted per
                     second.

              rxmcst/s
                     Number of  multicast  packets  received  per
                     second.

              With  the  EDEV  keyword,  statistics  on  failures
              (errors) from the  network  devices  are  reported.
              The following values are displayed:

              IFACE

              rxdrop/s
                     Number  of received packets dropped per sec­
                     ond because of a  lack  of  space  in  linux
                     buffers.

              txdrop/s
                     Number  of  transmitted  packets dropped per
                     second because of a lack of space  in  linux
                     buffers.

              txcarr/s
                     Number  of  carrier-errors that happened per
                     second while transmitting packets.

              rxfram/s
                     Number of frame alignment errors  that  hap­
                     pened per second on received packets.

              rxfifo/s
                     Number  of FIFO overrun errors that happened
                     per second on received packets.

              txfifo/s
                     Number of FIFO overrun errors that  happened
                     per second on transmitted packets.

              With the SOCK keyword, statistics on sockets in use
              are reported.  The following values are displayed:

              totsck
                     Total number of used sockets.

              tcpsck
                     Number of TCP sockets currently in use.

              udpsck
                     Number of UDP sockets currently in use.

              rawsck
                     Number of RAW sockets currently in use.

              ip-frag
                     Number of IP fragments currently in use.

              The FULL keyword is equivalent  to  specifying  all
              the  keywords  above  and therefore all the network
              activities are reported.

       -o filename
              Save the readings in the file in binary form.  Each
              reading  is in a separate record. The default value
              ldavg-1
                     System load average for the last minute.

              ldavg-5
                     System load average for the past 5  minutes.

       -r     Report  memory  and  swap space utilization statis­
              tics.  The following values are displayed:

              kbmemfree
                     Amount of free  memory  available  in  kilo­
                     bytes.

              kbmemused
                     Amount  of  used  memory  in kilobytes. This
                     does not take into account  memory  used  by
                     the kernel itself.

              %memused
                     Percentage of used memory.

              kbmemshrd
                     Amount  of  memory  shared  by the system in
                     kilobytes.  Always zero with 2.4 kernels.

              kbbuffers
                     Amount of memory used as buffers by the ker­
                     nel in kilobytes.

              kbcached
                     Amount  of  memory used to cache data by the
                     kernel in kilobytes.

              kbswpfree
                     Amount of free swap space in kilobytes.

              kbswpused
                     Amount of used swap space in kilobytes.

              %swpused
                     Percentage of used swap space.

       -R     Report memory statistics. The following values  are
              displayed:

              frmpg/s
                     Number  of  memory pages freed by the system
                     per second.  A negative value  represents  a
                     number  of  pages  allocated  by the system.
                     Note that a page has a size of 4 kB or 8  kB
                     according to the machine architecture.

                     means fewer pages in the cache.

       -s hh:mm:ss
              Set the starting time of the data, causing the  sar
              command  to extract records time-tagged at, or fol­
              lowing, the time specified.  The  default  starting
              time is 08:00.  Hours must be given in 24-hour for­
              mat. This option can be used  only  when  data  are
              read from a file (option -f ).

       -t     When  reading data from a daily data file, indicate
              that sar should display the timestamps in the orig­
              inal  locale time of the data file creator. Without
              this option, the sar command  displays  the  times­
              tamps in the user locale time.  When this option is
              used together with option -H, the timestamp is dis­
              played  in  local  time instead of UTC (Coordinated
              Universal  Time).   This  option  is  ignored  when
              option -h is used.

       -u     Report  CPU  utilization.  The following values are
              displayed:

              %user
                     Percentage of CPU utilization that  occurred
                     while  executing at the user level (applica­
                     tion).

              %nice
                     Percentage of CPU utilization that  occurred
                     while  executing at the user level with nice
                     priority.

              %system
                     Percentage of CPU utilization that  occurred
                     while  executing  at  the system level (ker­
                     nel).

              %idle
                     Percentage of time that the CPU or CPUs were
                     idle.

       -U cpu | ALL
              Report  CPU utilization for a given processor.  cpu
              is the processor number. The ALL keyword  indicates
              that  statistics are to be reported for all proces­
              sors. Note that processor 0 is the first processor.

       -v     Report  status  of  inode,  file  and  other kernel
              tables.  The following values are displayed:

              dentunusd
              super-sz
                     Number  of super block handlers allocated by
                     the kernel.

              %super-sz
                     Percentage of allocated super block handlers
                     with  regard  to the maximum number of super
                     block handlers that Linux can allocate.

              dquot-sz
                     Number of allocated disk quota entries.

              %dquot-sz
                     Percentage of allocated disk  quota  entries
                     with  regard to the maximum number of cached
                     disk quota entries that can be allocated.

              rtsig-sz
                     Number of queued RT signals.

              %rtsig-sz
                     Percentage of queued RT signals with  regard
                     to the maximum number of RT signals that can
                     be queued.

       -V     Print version number and usage then exit.

       -w     Report system switching activity.

              cswch/s
                     Total number of context switches per second.

       -W     Report  swapping  statistics.  The following values
              are displayed:

              pswpin/s
                     Total  number  of  swap  pages  the   system
                     brought in per second.

              pswpout/s
                     Total   number  of  swap  pages  the  system
                     brought out per second.

       -x pid | SELF | SUM | ALL
              Report statistics for a given process.  pid is  the
              process  identification  number.  The  SELF keyword
              indicates that statistics are to  be  reported  for
              the  sar  process  itself,  whereas the ALL keyword
              indicates that statistics are to  be  reported  for
              all  the system processes.  When the SUM keyword is
              used, the total number of minor  and  major  faults
              made  by  the system is reported. All these statis­
                     Total number of major faults the process has
                     made  per  second, those which have required
                     loading a memory page from disk.

              %user
                     Percentage of CPU used by the process  while
                     executing at the user level (application).

              %system
                     Percentage  of CPU used by the process while
                     executing at the system level (kernel).

              nswap/s
                     Number of pages  from  the  process  address
                     space the system has swapped out per second.

              CPU
                     Processor number to  which  the  process  is
                     attached.

              When  the  SUM keyword is used on the command line,
              the following values are displayed:

              minflt/s
                     Total number of minor faults the system  has
                     made   per  second,  those  which  have  not
                     required loading a memory page from disk.

              majflt/s
                     Total number of major faults the system  has
                     made  per  second, those which have required
                     loading a memory page from disk.

              These last two statistics are consistent only  when
              no  processes  have  terminated.   If  a process is
              killed during the interval, the statistics are  not
              available  (marked  as ????) and the average number
              will not be computed.

       -X pid | SELF | ALL
              Report statistics for the child  processes  of  the
              process  whose PID is pid .  The SELF keyword indi­
              cates that statistics are to be  reported  for  the
              child  processes of the sar process itself, whereas
              the ALL keyword indicates that statistics are to be
              reported  for  all  the  child processes of all the
              system processes.  All these statistics  cannot  be
              saved  to  a  file.  So this option will be ignored
              whenever -o option is used.  At the  present  time,
              no  more than 256 processes can be monitored simul­
              taneously.  The following values are displayed:

                     cesses  while  executing  at  the user level
                     (application).

              %csystem
                     Percentage of CPU used  by  the  child  pro­
                     cesses  while  executing at the system level
                     (kernel).

              cnswap/s
                     Number  of  pages  from  the  child  process
                     address  spaces  the  system has swapped out
                     per second.

       -y     Report TTY device activity.  The  following  values
              are displayed:

              rcvin/s
                     Number  of receive interrupts per second for
                     current serial line. Serial line  number  is
                     given in the TTY column.

              xmtin/s
                     Number of transmit interrupts per second for
                     current serial line.


ENVIRONMENT

       The sar command takes into account the following  environ­
       ment variable:

       S_TIME_FORMAT
              If  this  variable exists and its value is ISO then
              the current locale will be  ignored  when  printing
              the  date  in  the  report header.  The sar command
              will use the ISO format (YYYY-MM-DD) instead.


EXAMPLES

       sar -u 2 5
              Report CPU utilization for each 2 seconds. 5  lines
              are displayed.

       sar -I 14 -o int14.file 2 10
              Report  statistics on IRQ 14 for each 2 seconds. 10
              lines are displayed.  Data are  stored  in  a  file
              called int14.file.

       sar -r -n DEV -f /var/log/sa/sa16
              Display  memory,  swap space and network statistics
              saved in daily data file 'sa16'.


FILES

       /var/log/sa/sadd
              Indicate the daily data file, where the dd  parame­
              ter  is a number representing the day of the month.

       /proc contains various files with system statistics.


AUTHOR

       Sebastien Godard <sebastien.godard@wanadoo.fr>


SEE ALSO

       sadc(8), sa1(8), sa2(8),  isag(1),  mpstat(1),  iostat(1),
       vmstat(8)

       http://perso.wanadoo.fr/sebastien.godard/

Linux                      OCTOBER 2001                    SAR(1)
  




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