Monitoring Tools

20 Netstat Commands for Linux Network Management

20 Netstat Commands for Linux Network Management &-8211; this Article or News was published on this date:2019-05-28 20:00:45 kindly share it with friends if you find it helpful

netstat (network statistics) is a command line tool for monitoring network connections both incoming and outgoing as well as viewing routing tables, interface statistics etc. netstat is available on all Unix-like Operating Systems and also available on Windows OS as well. It is very useful in terms of network troubleshooting and performance measurement. netstat is one of the most basic network service debugging tools, telling you what ports are open and whether any programs are listening on ports.

Linux Netstat CommandLinux Netstat Command

Linux Netstat Command

This tool is very important and much useful for Linux network administrators as well as system administrators to monitor and troubleshoot their network related problems and determine network traffic performance. This article shows usages of netstat command with their examples which may be useful in daily operation.

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  1. 35 Practical Examples of Linux Find Command

1. Listing all the LISTENING Ports of TCP and UDP connections

Listing all ports (both TCP and UDP) using netstat -a option.

- netstat -a | more

Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address               Foreign Address             State
tcp        0      0 *:sunrpc                    *:*                         LISTEN
tcp        0     52 192.168.0.2:ssh             192.168.0.1:egs             ESTABLISHED
tcp        1      0 192.168.0.2:59292           www.gov.com:http            CLOSE_WAIT
tcp        0      0 localhost:smtp              *:*                         LISTEN
tcp        0      0 *:59482                     *:*                         LISTEN
udp        0      0 *:35036                     *:*
udp        0      0 *:npmp-local                *:*

Active UNIX domain sockets (servers and established)
Proto RefCnt Flags       Type       State         I-Node Path
unix  2      [ ACC ]     STREAM     LISTENING     16972  /tmp/orbit-root/linc-76b-0-6fa08790553d6
unix  2      [ ACC ]     STREAM     LISTENING     17149  /tmp/orbit-root/linc-794-0-7058d584166d2
unix  2      [ ACC ]     STREAM     LISTENING     17161  /tmp/orbit-root/linc-792-0-546fe905321cc
unix  2      [ ACC ]     STREAM     LISTENING     15938  /tmp/orbit-root/linc-74b-0-415135cb6aeab

2. Listing TCP Ports connections

Listing only TCP (Transmission Control Protocol) port connections using netstat -at.

- netstat -at

Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address               Foreign Address             State
tcp        0      0 *:ssh                       *:*                         LISTEN
tcp        0      0 localhost:ipp               *:*                         LISTEN
tcp        0      0 localhost:smtp              *:*                         LISTEN
tcp        0     52 192.168.0.2:ssh             192.168.0.1:egs             ESTABLISHED
tcp        1      0 192.168.0.2:59292           www.gov.com:http            CLOSE_WAIT

3. Listing UDP Ports connections

Listing only UDP (User Datagram Protocol ) port connections using netstat -au.

- netstat -au

Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address               Foreign Address             State
udp        0      0 *:35036                     *:*
udp        0      0 *:npmp-local                *:*
udp        0      0 *:mdns                      *:*

4. Listing all LISTENING Connections

Listing all active listening ports connections with netstat -l.

- netstat -l

Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address               Foreign Address             State
tcp        0      0 *:sunrpc                    *:*                         LISTEN
tcp        0      0 *:58642                     *:*                         LISTEN
tcp        0      0 *:ssh                       *:*                         LISTEN
udp        0      0 *:35036                     *:*
udp        0      0 *:npmp-local                *:*

Active UNIX domain sockets (only servers)
Proto RefCnt Flags       Type       State         I-Node Path
unix  2      [ ACC ]     STREAM     LISTENING     16972  /tmp/orbit-root/linc-76b-0-6fa08790553d6
unix  2      [ ACC ]     STREAM     LISTENING     17149  /tmp/orbit-root/linc-794-0-7058d584166d2
unix  2      [ ACC ]     STREAM     LISTENING     17161  /tmp/orbit-root/linc-792-0-546fe905321cc
unix  2      [ ACC ]     STREAM     LISTENING     15938  /tmp/orbit-root/linc-74b-0-415135cb6aeab

5. Listing all TCP Listening Ports

Listing all active listening TCP ports by using option netstat -lt.

- netstat -lt

Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address               Foreign Address             State
tcp        0      0 *:dctp                      *:*                         LISTEN
tcp        0      0 *:mysql                     *:*                         LISTEN
tcp        0      0 *:sunrpc                    *:*                         LISTEN
tcp        0      0 *:munin                     *:*                         LISTEN
tcp        0      0 *:ftp                       *:*                         LISTEN
tcp        0      0 localhost.localdomain:ipp   *:*                         LISTEN
tcp        0      0 localhost.localdomain:smtp  *:*                         LISTEN
tcp        0      0 *:http                      *:*                         LISTEN
tcp        0      0 *:ssh                       *:*                         LISTEN
tcp        0      0 *:https                     *:*                         LISTEN

6. Listing all UDP Listening Ports

Listing all active listening UDP ports by using option netstat -lu.

- netstat -lu

Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address               Foreign Address             State
udp        0      0 *:39578                     *:*
udp        0      0 *:meregister                *:*
udp        0      0 *:vpps-qua                  *:*
udp        0      0 *:openvpn                   *:*
udp        0      0 *:mdns                      *:*
udp        0      0 *:sunrpc                    *:*
udp        0      0 *:ipp                       *:*
udp        0      0 *:60222                     *:*
udp        0      0 *:mdns                      *:*

7. Listing all UNIX Listening Ports

Listing all active UNIX listening ports using netstat -lx.

- netstat -lx

Active UNIX domain sockets (only servers)
Proto RefCnt Flags       Type       State         I-Node Path
unix  2      [ ACC ]     STREAM     LISTENING     4171   @ISCSIADM_ABSTRACT_NAMESPACE
unix  2      [ ACC ]     STREAM     LISTENING     5767   /var/run/cups/cups.sock
unix  2      [ ACC ]     STREAM     LISTENING     7082   @/tmp/fam-root-
unix  2      [ ACC ]     STREAM     LISTENING     6157   /dev/gpmctl
unix  2      [ ACC ]     STREAM     LISTENING     6215   @/var/run/hald/dbus-IcefTIUkHm
unix  2      [ ACC ]     STREAM     LISTENING     6038   /tmp/.font-unix/fs7100
unix  2      [ ACC ]     STREAM     LISTENING     6175   /var/run/avahi-daemon/socket
unix  2      [ ACC ]     STREAM     LISTENING     4157   @ISCSID_UIP_ABSTRACT_NAMESPACE
unix  2      [ ACC ]     STREAM     LISTENING     60835836 /var/lib/mysql/mysql.sock
unix  2      [ ACC ]     STREAM     LISTENING     4645   /var/run/audispd_events
unix  2      [ ACC ]     STREAM     LISTENING     5136   /var/run/dbus/system_bus_socket
unix  2      [ ACC ]     STREAM     LISTENING     6216   @/var/run/hald/dbus-wsUBI30V2I
unix  2      [ ACC ]     STREAM     LISTENING     5517   /var/run/acpid.socket
unix  2      [ ACC ]     STREAM     LISTENING     5531   /var/run/pcscd.comm

8. Showing Statistics by Protocol

Displays statistics by protocol. By default, statistics are shown for the TCP, UDP, ICMP, and IP protocols. The -s parameter can be used to specify a set of protocols.

- netstat -s

Ip:
    2461 total packets received
    0 forwarded
    0 incoming packets discarded
    2431 incoming packets delivered
    2049 requests sent out
Icmp:
    0 ICMP messages received
    0 input ICMP message failed.
    ICMP input histogram:
    1 ICMP messages sent
    0 ICMP messages failed
    ICMP output histogram:
        destination unreachable: 1
Tcp:
    159 active connections openings
    1 passive connection openings
    4 failed connection attempts
    0 connection resets received
    1 connections established
    2191 segments received
    1745 segments send out
    24 segments retransmited
    0 bad segments received.
    4 resets sent
Udp:
    243 packets received
    1 packets to unknown port received.
    0 packet receive errors
    281 packets sent

9. Showing Statistics by TCP Protocol

Showing statistics of only TCP protocol by using option netstat -st.

- netstat -st

Tcp:
    2805201 active connections openings
    1597466 passive connection openings
    1522484 failed connection attempts
    37806 connection resets received
    1 connections established
    57718706 segments received
    64280042 segments send out
    3135688 segments retransmited
    74 bad segments received.
    17580 resets sent

10. Showing Statistics by UDP Protocol

- netstat -su

Udp:
    1774823 packets received
    901848 packets to unknown port received.
    0 packet receive errors
    2968722 packets sent

11. Displaying Service name with PID

Displaying service name with their PID number, using option netstat -tp will display “PID/Program Name”.

- netstat -tp

Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address               Foreign Address             State       PID/Program name
tcp        0      0 192.168.0.2:ssh             192.168.0.1:egs             ESTABLISHED 2179/sshd
tcp        1      0 192.168.0.2:59292           www.gov.com:http            CLOSE_WAIT  1939/clock-applet

12. Displaying Promiscuous Mode

Displaying Promiscuous mode with -ac switch, netstat print the selected information or refresh screen every five second. Default screen refresh in every second.

- netstat -ac 5 | grep tcp

tcp        0      0 *:sunrpc                    *:*                         LISTEN
tcp        0      0 *:58642                     *:*                         LISTEN
tcp        0      0 *:ssh                       *:*                         LISTEN
tcp        0      0 localhost:ipp               *:*                         LISTEN
tcp        0      0 localhost:smtp              *:*                         LISTEN
tcp        1      0 192.168.0.2:59447           www.gov.com:http            CLOSE_WAIT
tcp        0     52 192.168.0.2:ssh             192.168.0.1:egs             ESTABLISHED
tcp        0      0 *:sunrpc                    *:*                         LISTEN
tcp        0      0 *:ssh                       *:*                         LISTEN
tcp        0      0 localhost:ipp               *:*                         LISTEN
tcp        0      0 localhost:smtp              *:*                         LISTEN
tcp        0      0 *:59482                     *:*                         LISTEN

13. Displaying Kernel IP routing

Display Kernel IP routing table with netstat and route command.

- netstat -r

Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
192.168.0.0     *               255.255.255.0   U         0 0          0 eth0
link-local      *               255.255.0.0     U         0 0          0 eth0
default         192.168.0.1     0.0.0.0         UG        0 0          0 eth0

14. Showing Network Interface Transactions

Showing network interface packet transactions including both transferring and receiving packets with MTU size.

- netstat -i

Kernel Interface table
Iface       MTU Met    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
eth0       1500   0     4459      0      0      0     4057      0      0      0 BMRU
lo        16436   0        8      0      0      0        8      0      0      0 LRU

15. Showing Kernel Interface Table

Showing Kernel interface table, similar to ifconfig command.

- netstat -ie

Kernel Interface table
eth0      Link encap:Ethernet  HWaddr 00:0C:29:B4:DA:21
          inet addr:192.168.0.2  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:feb4:da21/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:4486 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4077 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:2720253 (2.5 MiB)  TX bytes:1161745 (1.1 MiB)
          Interrupt:18 Base address:0x2000

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:8 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:480 (480.0 b)  TX bytes:480 (480.0 b)

16. Displaying IPv4 and IPv6 Information

Displays multicast group membership information for both IPv4 and IPv6.

- netstat -g

IPv6/IPv4 Group Memberships
Interface       RefCnt Group
--------------- ------ ---------------------
lo              1      all-systems.mcast.net
eth0            1      224.0.0.251
eth0            1      all-systems.mcast.net
lo              1      ff02::1
eth0            1      ff02::202
eth0            1      ff02::1:ffb4:da21
eth0            1      ff02::1

17. Print Netstat Information Continuously

To get netstat information every few second, then use the following command, it will print netstat information continuously, say every few seconds.

- netstat -c

Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address               Foreign Address             State
tcp        0      0 sfnews.com:http   sg2nlhg007.shr.prod.s:36944 TIME_WAIT
tcp        0      0 sfnews.com:http   sg2nlhg010.shr.prod.s:42110 TIME_WAIT
tcp        0    132 sfnews.com:ssh    115.113.134.3.static-:64662 ESTABLISHED
tcp        0      0 sfnews.com:http   crawl-66-249-71-240.g:41166 TIME_WAIT
tcp        0      0 localhost.localdomain:54823 localhost.localdomain:smtp  TIME_WAIT
tcp        0      0 localhost.localdomain:54822 localhost.localdomain:smtp  TIME_WAIT
tcp        0      0 sfnews.com:http   sg2nlhg010.shr.prod.s:42091 TIME_WAIT
tcp        0      0 sfnews.com:http   sg2nlhg007.shr.prod.s:36998 TIME_WAIT

18. Finding non supportive Address

Finding un-configured address families with some useful information.

- netstat --verbose

netstat: no support for `AF IPX' on this system.
netstat: no support for `AF AX25' on this system.
netstat: no support for `AF X25' on this system.
netstat: no support for `AF NETROM' on this system.

19. Finding Listening Programs

Find out how many listening programs running on a port.

- netstat -ap | grep http

tcp        0      0 *:http                      *:*                         LISTEN      9056/httpd
tcp        0      0 *:https                     *:*                         LISTEN      9056/httpd
tcp        0      0 sfnews.com:http   sg2nlhg008.shr.prod.s:35248 TIME_WAIT   -
tcp        0      0 sfnews.com:http   sg2nlhg007.shr.prod.s:57783 TIME_WAIT   -
tcp        0      0 sfnews.com:http   sg2nlhg007.shr.prod.s:57769 TIME_WAIT   -
tcp        0      0 sfnews.com:http   sg2nlhg008.shr.prod.s:35270 TIME_WAIT   -
tcp        0      0 sfnews.com:http   sg2nlhg009.shr.prod.s:41637 TIME_WAIT   -
tcp        0      0 sfnews.com:http   sg2nlhg009.shr.prod.s:41614 TIME_WAIT   -
unix  2      [ ]         STREAM     CONNECTED     88586726 10394/httpd

20. Displaying RAW Network Statistics

- netstat --statistics --raw

Ip:
    62175683 total packets received
    52970 with invalid addresses
    0 forwarded
Icmp:
    875519 ICMP messages received
        destination unreachable: 901671
        echo request: 8
        echo replies: 16253
IcmpMsg:
        InType0: 83
IpExt:
    InMcastPkts: 117

That’s it, If you are looking for more information and options about netstat command, refer netstat manual docs or use man netstat command to know all the information. If we’ve missed anything in the list, please inform us using our comment section below. So, we could keep updating this list based on your comments.

Linux Performance Monitoring with Vmstat and Iostat Commands

Linux Performance Monitoring with Vmstat and Iostat Commands &-8211; this Article or News was published on this date:2019-05-28 19:58:35 kindly share it with friends if you find it helpful

This is our on-going series of commands and performance monitoring in Linux. Vmstat and Iostat both commands are available on all major Unix-like (Linux/Unix/FreeBSD/Solaris) Operating Systems.

If vmstat and iostat commands are not available on your box, please install sysstat package. The vmstat, sar and iostat commands are the collection of package included in sysstat – the system monitoring tools. The iostat generates reports of CPU & all device statistics. You may download and install sysstat using source tarball from link sysstat, but we recommend installing through YUM command.

Linux Vmstat and Iostat CommandsLinux Vmstat and Iostat Commands

Linux Performance Monitoring with Vmstat and Iostat

Install Sysstat in Linux

- yum -y install sysstat
  1. vmstat – Summary information of Memory, Processes, Paging etc.
  2. iostat – Central Processing Unit (CPU) statistics and input/output statistics for devices and partitions.
6 Vmstat Command Examples in Linux

1. List Active and Inactive Memory

In the below example, there are six columns. The significant of the columns are explained in man page of vmstat in details. Most important fields are free under memory and si, so under swap column.

[[email protected] ~]- vmstat -a

procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
 r  b   swpd   free  inact active   si   so    bi    bo   in   cs us sy id wa st
 1  0      0 810420  97380  70628    0    0   115     4   89   79  1  6 90  3  0
    1. Free – Amount of free/idle memory spaces.
    2. si – Swaped in every second from disk in Kilo Bytes.
    3. so – Swaped out every second to disk in Kilo Bytes.

Note: If you run vmstat without parameters it’ll displays summary report since system boot.

2. Execute vmstat ‘X’ seconds and (‘N’number of times)

With this command, vmstat execute every two seconds and stop automatically after executing six intervals.

[[email protected] ~]- vmstat 2 6

procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 0  0      0 810420  22064 101368    0    0    56     3   50   57  0  3 95  2  0
 0  0      0 810412  22064 101368    0    0     0     0   16   35  0  0 100  0  0
 0  0      0 810412  22064 101368    0    0     0     0   14   35  0  0 100  0  0
 0  0      0 810412  22064 101368    0    0     0     0   17   38  0  0 100  0  0
 0  0      0 810412  22064 101368    0    0     0     0   17   35  0  0 100  0  0
 0  0      0 810412  22064 101368    0    0     0     0   18   36  0  1 100  0  0

3. Vmstat with timestamps

vmstat command with -t parameter shows timestamps with every line printed as shown below.

[[email protected] ~]$ vmstat -t 1 5

procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------ ---timestamp---
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 0  0      0 632028  24992 192244    0    0    70     5   55   78  1  3 95  1  0        2012-09-02 14:57:18 IST
 1  0      0 632028  24992 192244    0    0     0     0  171  514  1  5 94  0  0        2012-09-02 14:57:19 IST
 1  0      0 631904  24992 192244    0    0     0     0  195  600  0  5 95  0  0        2012-09-02 14:57:20 IST
 0  0      0 631780  24992 192244    0    0     0     0  156  524  0  5 95  0  0        2012-09-02 14:57:21 IST
 1  0      0 631656  24992 192244    0    0     0     0  189  592  0  5 95  0  0        2012-09-02 14:57:22 IST

4. Statistics of Various Counter

vmstat command and -s switch displays summary of various event counters and memory statistics.

[[email protected] ~]$ vmstat -s

      1030800  total memory
       524656  used memory
       277784  active memory
       185920  inactive memory
       506144  free memory
        26864  buffer memory
       310104  swap cache
      2064376  total swap
            0  used swap
      2064376  free swap
         4539 non-nice user cpu ticks
            0 nice user cpu ticks
        11569 system cpu ticks
       329608 idle cpu ticks
         5012 IO-wait cpu ticks
           79 IRQ cpu ticks
           74 softirq cpu ticks
            0 stolen cpu ticks
       336038 pages paged in
        67945 pages paged out
            0 pages swapped in
            0 pages swapped out
       258526 interrupts
       392439 CPU context switches
   1346574857 boot time
         2309 forks

5. Disks Statistics

vmstat with -d option display all disks statistics.

[[email protected] ~]$ vmstat -d

disk- ------------reads------------ ------------writes----------- -----IO------
       total merged sectors      ms  total merged sectors      ms    cur    sec
ram0       0      0       0       0      0      0       0       0      0      0
ram1       0      0       0       0      0      0       0       0      0      0
ram2       0      0       0       0      0      0       0       0      0      0
ram3       0      0       0       0      0      0       0       0      0      0
ram4       0      0       0       0      0      0       0       0      0      0
ram5       0      0       0       0      0      0       0       0      0      0
ram6       0      0       0       0      0      0       0       0      0      0
ram7       0      0       0       0      0      0       0       0      0      0
ram8       0      0       0       0      0      0       0       0      0      0
ram9       0      0       0       0      0      0       0       0      0      0
ram10      0      0       0       0      0      0       0       0      0      0
ram11      0      0       0       0      0      0       0       0      0      0
ram12      0      0       0       0      0      0       0       0      0      0
ram13      0      0       0       0      0      0       0       0      0      0
ram14      0      0       0       0      0      0       0       0      0      0
ram15      0      0       0       0      0      0       0       0      0      0
loop0      0      0       0       0      0      0       0       0      0      0
loop1      0      0       0       0      0      0       0       0      0      0
loop2      0      0       0       0      0      0       0       0      0      0
loop3      0      0       0       0      0      0       0       0      0      0
loop4      0      0       0       0      0      0       0       0      0      0
loop5      0      0       0       0      0      0       0       0      0      0
loop6      0      0       0       0      0      0       0       0      0      0
loop7      0      0       0       0      0      0       0       0      0      0
sr0        0      0       0       0      0      0       0       0      0      0
sda     7712   5145  668732  409619   3282  28884  257402  644566      0    126
dm-0   11578      0  659242 1113017  32163      0  257384 8460026      0    126
dm-1     324      0    2592    3845      0      0       0       0      0      2

6. Display Statistics in Megabytes

The vmstat displays in Megabytes with parameters -S and M(Uppercase & megabytes). By default vmstat displays statistics in kilobytes.

[[email protected] ~]- vmstat -S M 1 5

procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 0  0      0    346     53    476    0    0    95     8   42   55  0  2 96  2  0
 0  0      0    346     53    476    0    0     0     0   12   15  0  0 100  0  0
 0  0      0    346     53    476    0    0     0     0   32   62  0  0 100  0  0
 0  0      0    346     53    476    0    0     0     0   15   13  0  0 100  0  0
 0  0      0    346     53    476    0    0     0     0   34   61  0  1 99  0  0
6 Iostat Command Examples in Linux

7. Display CPU and I/O statistics

iostat without arguments displays CPU and I/O statistics of all partitions as shown below.

[[email protected] ~]- iostat

Linux 2.6.32-279.el6.i686 (sfnews.com)         09/03/2012      _i686_  (1 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.12    0.01    1.54    2.08    0.00   96.24

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
sda               3.59       161.02        13.48    1086002      90882
dm-0              5.76       159.71        13.47    1077154      90864
dm-1              0.05         0.38         0.00       2576          0

8. Shows only CPU Statistics

iostat with -c arguments displays only CPU statistics as shown below.

[[email protected] ~]- iostat -c

Linux 2.6.32-279.el6.i686 (sfnews.com)         09/03/2012      _i686_  (1 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.12    0.01    1.47    1.98    0.00   96.42

9. Shows only Disks I/O Statistics

iostat with -d arguments displays only disks I/O statistics of all partitions as shown.

[[email protected] ~]- iostat -d

Linux 2.6.32-279.el6.i686 (sfnews.com)         09/03/2012      _i686_  (1 CPU)

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
sda               3.35       149.81        12.66    1086002      91746
dm-0              5.37       148.59        12.65    1077154      91728
dm-1              0.04         0.36         0.00       2576          0

10. Shows I/O statistics only of a single device.

By default it displays statistics of all partitions, with -p and device name arguments displays only disks I/O statistics for specific device only as shown.

[[email protected] ~]- iostat -p sda

Linux 2.6.32-279.el6.i686 (sfnews.com)         09/03/2012      _i686_  (1 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.11    0.01    1.44    1.92    0.00   96.52

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
sda               3.32       148.52        12.55    1086002      91770
sda1              0.07         0.56         0.00       4120         18
sda2              3.22       147.79        12.55    1080650      91752

11. Display LVM Statistics

With -N (Uppercase) parameter displays only LVM statistics as shown.

[[email protected] ~]- iostat -N

Linux 2.6.32-279.el6.i686 (sfnews.com)         09/03/2012      _i686_  (1 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.11    0.01    1.39    1.85    0.00   96.64

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
sda               3.20       142.84        12.16    1086002      92466
vg_sfnews-lv_root     5.13       141.68        12.16    1077154      92448
vg_sfnews-lv_swap     0.04         0.34         0.00       2576          0

12. iostat version.

With -V (Uppercase) parameter displays version of iostat as shown.

[[email protected] ~]- iostat -V

sysstat version 9.0.4
(C) Sebastien Godard (sysstat  orange.fr)

Note: vmstat and iostat contains number of columns and flags which may not possible to explain in details. If you want to know more about it you may refer man page of vmstat and iostat. Please share it if you find this article is useful through our comment box below.