how to use mptstat and iostat to gather statistical information about CPU, RAM and Disk usage.

mpstat_iostat.txt

### mpstat command ###

# all cpu utilization
mpstat -A

# processor utilization by CPU
mpstat -P 0
mpstat -P 1

# gather multiple reports over time
## this will create a total of 6 reports, outputting one report every 10 seconds
mpstat 10 6

# output of mpstat explained:
  CPU
         Processor number. The keyword all indicates  that  statistics  are
         calculated as averages among all processors.
  %usr
         Show the percentage of CPU utilization that occurred while execut‐
         ing at the user level (application).
  %nice
         Show the percentage of CPU utilization that occurred while execut‐
         ing at the user level with nice priority.
  %sys
         Show the percentage of CPU utilization that occurred while execut‐
         ing at the system level (kernel). Note that this does not  include
         time spent servicing hardware and software interrupts.
  %iowait
         Show  the percentage of time that the CPU or CPUs were idle during
         which the system had an outstanding disk I/O request.
  %irq
         Show the percentage of time spent by the CPU or  CPUs  to  service
         hardware interrupts.
  %soft
         Show  the  percentage  of time spent by the CPU or CPUs to service
         software interrupts.
  %steal
         Show the percentage of time spent in involuntary wait by the  vir‐
         tual  CPU  or CPUs while the hypervisor was servicing another vir‐
         tual processor.
  %guest
         Show the percentage of time spent by the CPU or CPUs to run a vir‐
         tual processor.
  %gnice
         Show  the  percentage  of  time  spent by the CPU or CPUs to run a
         niced guest.
  %idle: Show the percentage of time that the CPU or CPUs were idle and the system did not have an outstanding disk I/O request.


### iostat command ###

# iostat monitors system Input/Output
# use -t to timestamp each report
# use -x to report 'extended' statistics

# get a total of 6 reports, one every 10 seconds
iostat -tx 10 6


# cpu utilization report
iostat -c

# Output of iostat -c explained:
  %user
         Show the percentage of CPU utilization that occurred while execut‐
         ing at the user level (application).
  %nice
         Show the percentage of CPU utilization that occurred while execut‐
         ing at the user level with nice priority.
  %system
         Show the percentage of CPU utilization that occurred while execut‐
         ing at the system level (kernel).
  %iowait
         Show the percentage of time that the CPU or CPUs were idle  during
         which the system had an outstanding disk I/O request.
  %steal
         Show  the percentage of time spent in involuntary wait by the vir‐
         tual CPU or CPUs while the hypervisor was servicing  another  vir‐
         tual processor.
  %idle
         Show the percentage of time that the CPU or CPUs were idle and the
         system did not have an outstanding disk I/O request.


# device utilization report
iostat -d
# report on device mappers (similar to above, but gets LVM stats)
iostat -n 

# use -h to make device report human readable
# use -k to display device report in kilobytes / sec
# use -m to display device report in megabytes / sec

# Output of iostat -d explained:
 Device:
         This  column gives the device (or partition) name as listed in the
         /dev directory.
  tps
         Indicate the number of transfers per second that  were  issued  to
         the  device.  A transfer is an I/O request to the device. Multiple
         logical requests can be combined into a single I/O request to  the
         device. A transfer is of indeterminate size.
  Blk_read/s (kB_read/s, MB_read/s)
         Indicate  the  amount  of data read from the device expressed in a
         number of blocks (kilobytes, megabytes)  per  second.  Blocks  are
         equivalent to sectors and therefore have a size of 512 bytes.
  Blk_wrtn/s (kB_wrtn/s, MB_wrtn/s)
         Indicate  the  amount of data written to the device expressed in a
         number of blocks (kilobytes, megabytes) per second.
  Blk_read (kB_read, MB_read)
         The total number of blocks (kilobytes, megabytes) read.
  Blk_wrtn (kB_wrtn, MB_wrtn)
         The total number of blocks (kilobytes, megabytes) written.
  rrqm/s
         The number of read requests merged per second that were queued  to
         the device.
  wrqm/s
         The number of write requests merged per second that were queued to
         the device.
  r/s
         The number (after merges) of read requests  completed  per  second
         for the device.
  w/s
         The  number  (after merges) of write requests completed per second
         for the device.
  rsec/s (rkB/s, rMB/s)
         The number of sectors (kilobytes, megabytes) read from the  device
         per second.
  wsec/s (wkB/s, wMB/s)
         The number of sectors (kilobytes, megabytes) written to the device
         per second.
 avgrq-sz
         The average size (in sectors) of the requests that were issued  to
         the device.
  avgqu-sz
         The  average  queue length of the requests that were issued to the
         device.
  await
         The average time (in milliseconds) for I/O requests issued to  the
         device  to be served. This includes the time spent by the requests
         in queue and the time spent servicing them.
  r_await
         The average time (in milliseconds) for read requests issued to the
         device  to be served. This includes the time spent by the requests
         in queue and the time spent servicing them.
  w_await
         The average time (in milliseconds) for write  requests  issued  to
         the  device  to  be  served.  This  includes the time spent by the
         requests in queue and the time spent servicing them.
  svctm
         The average service time (in milliseconds) for I/O  requests  that
         were  issued  to  the device. Warning! Do not trust this field any
         more.  This field will be removed in a future sysstat version.
  %util
         Percentage of CPU time during which I/O requests  were  issued  to
         the  device (bandwidth utilization for the device). Device satura‐
         tion occurs when this value is close to 100% for  devices  serving
         requests  serially.  But for devices serving requests in parallel,
         such as RAID arrays and modern SSDs, this number does not  reflect
         their performance limits.