vmstat command

LINUX-Frequently used commands

vmstat command Display load factor and usage of memory and CPU.
vmstat  [Option] 
vmstat is a command that displays information about the system. For example, it displays the free space in the main memory, the CPU status, etc.
If you run the vmstat command verbatim, you will see the current process, memory, swap, device, interrupt, and CPU information.
With the -d and -p options, you can see the status of reading and writing to partitions and disks..
If the -f option is specified, the number of times a process was created between the time the system was started and the time the command was executed is displayed.
If you specify a time interval in seconds after vmstat, the system status will be displayed at each specified time.
If you specify a number of times, the information for the specified number of times will be displayed.
The unit of capacity can be specified with the "-S" option. If you specify "-S M", the unit of capacity is displayed in M bytes.
Frequently used options
-f          Display the number of forks (the number of times a process has been created)
-n          Display the header only once
-s          Display each piece of information with its detailed information name
-d        Display statistics for a given partition
-S <unit>  Displays the capacity in the specified units.    k is 1,000, K is 1,024, m is 1,000,000, M is 1,048,576 bytes Display in units
Example: View statistics.
$ su -  ← Become a super user root
Password: Enter root password
#  vmstat

Example: Memory and CPU information is displayed three times at 10-second intervals.
#  vmstat 10 3

Example: Display the number of fork.
#  vmstat -f
356579 forks
Example: Display information about reading and writing to partition /dev/hda1.
#  vmstat -p /dev/hda1

What the vmstat command displays(No options)
procs  Statistics on active processes
r:Number of processes waiting to run
b:Number of processes in non-interruptible sleep state
w:Number of processes swapped out and executable
memory  Data on the amount of memory used and available
swpd:Amount of virtual memory
free:Amount of free memory (Kbytes)
buff:Amount of memory used as buffer (Kbytes)
swap  Statistics on swaps
si:Amount of memory being swapped in from disk(Kバイト/秒)
so:Amount of memory swapped to disk (Kbytes/second)
iO  Transfer volume to and from devices
bi:Number of blocks received from the block device(blocks/second)
bo:Number of blocks sent to the block device (blocks/second)
system  System-wide interrupt and context switching rates
in:Number of interruptions per second
cs:Number of context switches per second
cpu  Percentage of CPU usage
us:User time
sy:System time
id:Idle time
wa:IO waiting time
What the vmstat command displays( "d" option)
disk Location of the file system
reads:Information about reading
total:Total number of successful reads
merged:Number of reads (when grouped)
sectors:Number of sectors successfully read
ms:Time taken to read
writes  Information on writing
total:Total number of successful writes
merged:Number of posts (when grouped)
sectors:Number of successfully written sectors
ms:Time taken to write
IO Input and output related information from the device
cur:Running IO
sec:Time used by IO
What the vmstat command displays( "p" option))
reads Number of reads from the specified partition
read sectors Number of sectors read from the specified partition
writes Number of writes to the specified partition
requested writes Number of write requests to the specified partition
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