.TH SAR 1 "OCTOBER 2001" Linux "Linux User's Manual" -*- nroff -*-
.SH NAME
sar \- Collect, report, or save system activity information.
.SH SYNOPSIS
.B sar [ -A ] [ -b ] [ -B ] [ -c ] [ -d ] [ -H ] [ -h ] [ -i
.I interval
.B ] [ -q ] [ -r ] [ -R ] [ -t ] [ -u ] [ -v ] [ -V ] [ -w ] [ -W ] [ -y ]
.B [ -n { DEV | EDEV | SOCK | FULL } ]
.B [ -x {
.I pid
.B | SELF | SUM | ALL } ] [ -X {
.I pid
.B | SELF | ALL } ] [ -I {
.I irq
.B | SUM | PROC | ALL | XALL } ] [ -U {
.I cpu
.B | ALL } ] [ -o [
.I filename
.B ] | -f [
.I filename
.B ] ] [ -s [
.I hh:mm:ss
.B ] ] [ -e [
.I hh:mm:ss
.B ] ] [
.I interval
.B [
.I count
.B ] ]
.SH DESCRIPTION
The
.B 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
.I count
and
.I interval
parameters, writes information the specified number of times spaced
at the specified intervals in seconds.
If the interval parameter is set to zero, the
.B sar
command displays the average statistics for the time
since the system was started. The default value for the
.I 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
.B -o
.I filename
flag, in addition to being displayed onto the screen. If
.I filename
is omitted, sar uses the standard system activity daily data file,
the
.IR /var/log/sa/sa dd
file, where the dd parameter indicates the current day.

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

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

The default version of the
.B sar
command (CPU utilization report) might be one of the first facilities
the user runs to begin system activity investigation, because it
monitors 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
.B sar
command. 
Run the
.B sar
command as a background process. The syntax for this is:

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

All data is captured in binary form and saved to a file (data.file).
The data can then be selectively displayed with the
.B sar
command using the
.B -f
option. Set the
.I count
parameter to select records at
.I count
second intervals. If this parameter is not set, all the records saved in the
file will be selected.
Collection of data in this manner is useful to characterize
system usage over a period of time and determine peak usage hours.

Note:	The
.B sar
command only reports on local activities.

.SH OPTIONS
.IP -A
This is equivalent to specifying
.BR "-bBcdqrRuvwWy -I SUM -I PROC -n FULL -U ALL".
.IP -b
Report I/O and transfer rate statistics. The following values are
displayed:

.B tps
.RS
.RS
Total number of transfers per second that were issued to the physical disk.
A transfer 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.
.RE

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

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

.B bread/s
.RS
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 kernels, a block is of
indeterminate size.
.RE

.B bwrtn/s
.RS
Total amount of data written to the drive in blocks per second.
.RE
.RE
.IP -B
Report paging statistics. The following values are displayed:

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

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

.B activepg
.RS
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 architecture.
.RE

.B inadtypg
.RS
Number of inactive dirty (modified or potentially modified) pages in memory.
.RE

.B inaclnpg
.RS
Number of inactive clean (not modified) pages in memory.
.RE

.B inatarpg
.RS
"Inactive target" number of pages. This field is a 1-minute floating average
of the number of pages the system needs to "steal" every second
in order to satisfy memory demand.
.RE
.RE
.IP -c
Report process creation activity.

.B proc/s
.RS
.RS
Total number of processes created per second.
.RE
.RE
.IP -d
Report activity for each block device (kernels 2.4 and later only). When data is displayed,
the device specification
.I dev m-n
is generally used (
.B DEV
column).
.B m
is the major number of the device, whereas
.B n
is a distinctive number.

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

.B sect/s
.RS
Number of sectors transferred from or to the device. The size of a sector is 512 bytes.
.RE
.RE
.IP "-e hh:mm:ss"
Set the ending time of the report. The default ending 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
.B -f
or
.B -o
).
.IP "-f filename"
Extract records from
.I filename
(created by the
.B -o filename
flag). The default value of the
.B filename
parameter is the current daily data file, the
.IR /var/log/sa/sa dd
file. The -f option is exclusive of the -o option.
.IP -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.
.IP -H
When  reading data from a file, print its contents in a format that can easily
be ingested by a relational database system. The output consists
of fields separated by a semicolon. Each record contains
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 databases, and additional semicolon separated data fields as specified
by other sar command line options.
.IP "-i interval"
Select data records at seconds as close as possible to the number specified
by the
.I interval
parameter.
.IP "-I irq | SUM | PROC | ALL | XALL"
Report statistics for a given interrupt.
.B irq
is the interrupt number. The
.B SUM
keyword indicates that the total number of interrupts received per second
is to be displayed. The
.B ALL
keyword indicates that statistics from
the first 16 interrupts are to be reported, whereas the
.B XALL
keyword indicates that statistics from all interrupts, including potential
APIC interrupt sources, are to be reported.
Last, if you use the
.B PROC
keyword, the number of interrupts per second received by each processor
is displayed.
.IP "-n DEV | EDEV | SOCK | FULL"
Report network statistics.

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

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

.B rxpck/s
.RS
Total number of packets received per second.
.RE

.B txpck/s
.RS
Total number of packets transmitted per second.
.RE

.B rxbyt/s
.RS
Total number of bytes received per second.
.RE

.B txbyt/s
.RS
Total number of bytes transmitted per second.
.RE

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

.B txcmp/s
.RS
Number of compressed packets transmitted per second.
.RE

.B rxmcst/s
.RS
Number of multicast packets received per second.
.RE

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

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

.B rxerr/s
.RS
Total number of bad packets received per second.
.RE

.B txerr/s
.RS
Total number of errors that happened per second while transmitting packets.
.RE

.B coll/s
.RS
Number of collisions that happened per second while transmitting packets.
.RE

.B rxdrop/s
.RS
Number of received packets dropped per second because of a lack of space in linux buffers.
.RE

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

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

.B rxfram/s
.RS
Number of frame alignment errors that happened per second on received packets.
.RE

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

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

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

.B totsck
.RS
Total number of used sockets.
.RE

.B tcpsck
.RS
Number of TCP sockets currently in use.
.RE

.B udpsck
.RS
Number of UDP sockets currently in use.
.RE

.B rawsck
.RS
Number of RAW sockets currently in use.
.RE

.B ip-frag
.RS
Number of IP fragments currently in use.
.RE

The
.B FULL
keyword is equivalent to specifying all the keywords above and therefore all the network
activities are reported.
.RE
.RE
.IP "-o filename"
Save the readings in the file in binary form. Each reading
is in a separate record. The default value of the
.B filename
parameter is the current daily data file, the
.IR /var/log/sa/sa dd
file. The -o option is exclusive of the -f option.
.IP -q
Report queue length and load averages. The following values are displayed:

.B runq-sz
.RS
.RS
Run queue length (number of processes waiting for run time). 
.RE

.B plist-sz
.RS
Number of processes in the process list.
.RE

.B ldavg-1
.RS
System load average for the last minute.
.RE

.B ldavg-5
.RS
System load average for the past 5 minutes.
.RE
.RE
.IP -r
Report memory and swap space utilization statistics.
The following values are displayed:

.B kbmemfree
.RS
.RS
Amount of free memory available in kilobytes.
.RE

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

.B %memused
.RS
Percentage of used memory.
.RE

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

.B kbbuffers
.RS
Amount of memory used as buffers by the kernel in kilobytes.
.RE

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

.B kbswpfree
.RS
Amount of free swap space in kilobytes.
.RE

.B kbswpused
.RS
Amount of used swap space in kilobytes.
.RE

.B %swpused
.RS
Percentage of used swap space.
.RE
.RE
.IP -R
Report memory statistics. The following values are displayed:

.B frmpg/s
.RS
.RS
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.
.RE

.B shmpg/s
.RS
Number of additionnal memory pages shared by the system per second.
A negative value means fewer pages shared by the system.
.RE

.B bufpg/s
.RS
Number of additionnal memory pages used as buffers by the system per second.
A negative value means fewer pages used as buffers by the system.
.RE

.B campg/s
.RS
Number of additionnal memory pages cached by the system per second.
A negative value means fewer pages in the cache.
.RE
.RE
.IP "-s hh:mm:ss"
Set the starting time of the data, causing the
.B sar
command to extract records time-tagged at, or following, the time
specified. The default starting time is 08:00.
Hours must be given in 24-hour format. This option can be
used only when data are read from a file (option
.B -f
).
.IP -t
When reading data from a daily data file, indicate that
.B sar
should display the timestamps in the original locale time of
the data file creator. Without this option, the
.B sar
command displays the timestamps in the user locale time.
.IP -u
Report CPU utilization. The following values are displayed:

.B %user
.RS
.RS
Percentage of CPU utilization that occurred while executing at the user
level (application).
.RE

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

.B %system
.RS
Percentage of CPU utilization that occurred while executing at the system
level (kernel).
.RE

.B %idle
.RS
Percentage of time that the CPU or CPUs were idle.
.RE
.RE
.IP "-U cpu | ALL"
Report CPU utilization for a given processor.
.B cpu
is the processor number. The
.B ALL
keyword indicates that statistics
are to be reported for all processors. Note that processor 0 is
the first processor.
.IP -v
Report status of inode, file and other kernel tables.
The following values are displayed:

.B dentunusd
.RS
.RS
Number of unused cache entries in the directory cache.
.RE

.B file-sz
.RS
Number of used file handles.
.RE

.B %file-sz
.RS
Percentage of used file handles with regard to the maximum number 
of file handles that the Linux kernel can allocate.
.RE

.B inode-sz
.RS
Number of used inode handlers.
.RE

.B super-sz
.RS
Number of super block handlers allocated by the kernel.
.RE

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

.B dquot-sz
.RS
Number of allocated disk quota entries.
.RE

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

.B rtsig-sz
.RS
Number of queued RT signals.
.RE

.B %rtsig-sz
.RS
Percentage of queued RT signals with regard to the maximum number
of RT signals that can be queued.
.RE
.RE
.IP -V
Print version number and usage then exit.
.IP -w
Report system switching activity.

.B cswch/s
.RS
.RS
Total number of context switches per second.
.RE
.RE
.IP -W
Report swapping statistics. The following values are displayed:

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

.B pswpout/s
.RS
Total number of swap pages the system brought out per second.
.RE
.RE
.IP "-x pid | SELF | SUM | ALL"
Report statistics for a given process.
.B pid
is the process identification number. The
.B SELF
keyword indicates that statistics are to be reported for the
.B sar
process itself, whereas the
.B ALL
keyword indicates that statistics are to be reported for all the system processes.
When the
.B SUM
keyword is used, the total number of minor and major faults made by the system
is reported. 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
simultaneously.

When the
.B SUM
keyword is not used, the following values are displayed:

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

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

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

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

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

.B CPU
.RS
Processor number to which the process is attached.
.RE

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

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

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

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.
.RE
.IP "-X pid | SELF | ALL"
Report statistics for the child processes of the process whose PID is
.B pid .
The
.B SELF
keyword indicates that statistics are to be reported for the child processes of the
.B sar
process itself, whereas the
.B 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
simultaneously.
The following values are displayed:

.B cminflt/s
.RS
.RS
Total number of minor faults the child processes have made per second, those
which have not required loading a memory page from disk.
.RE

.B cmajflt/s
.RS
Total number of major faults the child processes have made per second, those
which have required loading a memory page from disk.
.RE

.B %cuser
.RS
Percentage of CPU used by the child processes while executing at the user level
(application).
.RE

.B %csystem
.RS
Percentage of CPU used by the child processes while executing at the system level
(kernel).
.RE

.B cnswap/s
.RS
Number of pages from the child process address spaces the system has swapped out per second.
.RE
.RE
.IP -y
Report TTY device activity. The following values are displayed:

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

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

.SH ENVIRONMENT
The
.B sar
command takes into account the following environment variable:

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

.SH EXAMPLES
.B sar -u 2 5
.RS
Report CPU utilization for each 2 seconds. 5 lines are displayed.
.RE

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

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

.B sar -A
.RS
Display all the statistics saved in current daily data file.
.SH BUGS
.I /proc
filesystem must be mounted for the
.B sar
command to work.

All the statistics are not necessarily available, depending on the kernel version used.
In particular, TTY statistics (option -y) are not available in 2.2.x SMP kernels (with
x <= 15), because of an SMP race that
.B sar
may trigger when reading the
.I /proc/tty/driver/serial
file.
.SH FILES
.IR /var/log/sa/sa dd
.RS
Indicate the daily data file, where the
.B dd
parameter is a number representing the day of the month.

.RE
.IR /proc
contains various files with system statistics.
.SH AUTHOR
Sebastien Godard <sebastien.godard@wanadoo.fr>
.SH SEE ALSO
.BR sadc (8),
.BR sa1 (8),
.BR sa2 (8),
.BR isag (1),
.BR mpstat (1),
.BR iostat (1),
.BR vmstat (8)

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