iostat is Linux Command basically use for Performance Monitoring.
iostat reports CPU, disk I/O, and NFS statistics.
To display extended information for a specific partition (For example, /dev/sda1), do the following.
iostat reports CPU, disk I/O, and NFS statistics.
1. iostat – Basic example
Iostat without any argument displays information about the CPU usage, and I/O statistics about all the partitions on the system as shown below.$ iostat
Linux 2.6.32-100.28.5.el6.x86_64 (dev-db) 07/09/2011
avg-cpu: %user %nice %system %iowait %steal %idle
5.68 0.00 0.52 2.03 0.00 91.76
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 194.72 1096.66 1598.70 2719068704 3963827344
sda1 178.20 773.45 1329.09 1917686794 3295354888
sda2 16.51 323.19 269.61 801326686 668472456
sdb 371.31 945.97 1073.33 2345452365 2661206408
sdb1 371.31 945.95 1073.33 2345396901 2661206408
sdc 408.03 207.05 972.42 513364213 2411023092
sdc1 408.03 207.03 972.42 513308749 2411023092
2. iostat – Display only cpu statistics
iostat option -c, displays only the CPU usage statistics as shown below.$ iostat -c
Linux 2.6.32-100.28.5.el6.x86_64 (dev-db) 07/09/2011
avg-cpu: %user %nice %system %iowait %steal %idle
5.68 0.00 0.52 2.03 0.00 91.76
3. iostat – Display only disk I/O statistics
iostat option -d, displays only the disk I/O statistics as shown below.$ iostat -d
Linux 2.6.32-100.28.5.el6.x86_64 (dev-db) 07/09/2011
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 194.71 1096.61 1598.63 2719068720 3963827704
sda1 178.20 773.41 1329.03 1917686810 3295355248
sda2 16.51 323.18 269.60 801326686 668472456
sdb 371.29 945.93 1073.28 2345452365 2661209192
sdb1 371.29 945.91 1073.28 2345396901 2661209192
sdc 408.01 207.04 972.38 513364213 2411024484
sdc1 408.01 207.02 972.38 513308749 2411024484
4. iostat – Display only network statistics
iostat option -n, displays only the device and NFS statistics as shown below.
$ iostat -n
Linux 2.6.32-100.28.5.el6.x86_64 (dev-db) 07/09/2011
avg-cpu: %user %nice %sys %iowait %idle
4.33 0.01 1.16 0.31 94.19
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 2.83 0.35 5.39 29817402 457360056
sda1 3.32 50.18 4.57 4259963994 387641400
sda2 0.20 0.76 0.82 64685128 69718576
sdb 6.59 15.53 42.98 1318931178 3649084113
sdb1 11.80 15.53 42.98 1318713382 3649012985
Device: rBlk_nor/s wBlk_nor/s rBlk_dir/s wBlk_dir/s rBlk_svr/s wBlk_svr/s
192.168.1.4:/home/data 90.67 0.00 0.00 0.00 5.33 0.00
192.168.1.4:/backup 8.74 0.00 0.00 0.00 8.74 0.00
192.168.1.8:/media 0.02 0.00 0.00 0.00 0.01 0.00
5. iostat – Display I/O data in MB/second
By default iostat, displays the device I/O statistics in Blocks. To change it to MB, use -m as shown below.$ iostat -m
Linux 2.6.32-100.28.5.el6.x86_64 (dev-db) 07/09/2011
avg-cpu: %user %nice %system %iowait %steal %idle
5.68 0.00 0.52 2.03 0.00 91.76
Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn
sda 194.70 0.54 0.78 1327670 1935463
sda1 178.19 0.38 0.65 936370 1609060
sda2 16.51 0.16 0.13 391272 326402
sdb 371.27 0.46 0.52 1145240 1299425
sdb1 371.27 0.46 0.52 1145213 1299425
sdc 407.99 0.10 0.47 250666 1177259
sdc1 407.99 0.10 0.47 250639 1177259
6. iostat – Display I/O statistics only for a device
By default iostat displays I/O data for all the disks available in the system. To view statistics for a specific device (For example, /dev/sda), use the option -p as shown below.$ iostat -p sda
Linux 2.6.32-100.28.5.el6.x86_64 (dev-db) 07/09/2011
avg-cpu: %user %nice %system %iowait %steal %idle
5.68 0.00 0.52 2.03 0.00 91.76
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 194.69 1096.51 1598.48 2719069928 3963829584
sda2 336.38 27.17 54.00 67365064 133905080
sda1 821.89 0.69 243.53 1720833 603892838
7. iostat – Display timestamp information
By default iostat displays only the current date. To display the current time, use the option -t as shown below.
$ iostat -t
Linux 2.6.32-100.28.5.el6.x86_64 (dev-db) 07/09/2011
Time: 08:57:52 AM
avg-cpu: %user %nice %system %iowait %steal %idle
5.68 0.00 0.52 2.03 0.00 91.76
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 194.69 1096.49 1598.45 2719070384 3963829704
sda1 178.18 773.32 1328.88 1917688474 3295357248
sda2 16.51 323.14 269.57 801326686 668472456
sdb 371.25 945.82 1073.16 2345452741 2661228872
sdb1 371.25 945.80 1073.16 2345397277 2661228872
sdc 407.97 207.02 972.27 513364233 2411030200
sdc1 407.97 207.00 972.27 513308769 2411030200
8. iostat – Display Extended status
Use option -x, which will displays extended disk I/O statistics information as shown below.$ iostat -x
Linux 2.6.32-100.28.5.el6.x86_64 (dev-db) 07/09/2011
avg-cpu: %user %nice %system %iowait %steal %idle
5.68 0.00 0.52 2.03 0.00 91.76
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
sda 27.86 63.53 61.77 132.91 1096.46 1598.40 13.84 0.21 1.06 2.28 44.45
sda1 0.69 33.22 48.54 129.63 773.30 1328.84 11.80 1.39 7.82 2.28 40.57
sda2 27.16 30.32 13.23 3.28 323.13 269.56 35.90 0.55 32.96 3.44 5.68
sdb 39.15 215.16 202.20 169.04 945.80 1073.13 5.44 1.05 2.78 1.64 60.91
sdb1 39.15 215.16 202.20 169.04 945.77 1073.13 5.44 1.05 2.78 1.64 60.91
sdc 8.90 3.63 356.56 51.40 207.01 972.24 2.89 1.04 2.56 1.55 63.30
sdc1 8.90 3.63 356.55 51.40 206.99 972.24 2.89 1.04 2.56 1.55 63.30
To display extended information for a specific partition (For example, /dev/sda1), do the following.
$ iostat -x sda1
Linux 2.6.32-100.28.5.el6.x86_64 (dev-db) 07/09/2011
avg-cpu: %user %nice %system %iowait %steal %idle
5.68 0.00 0.52 2.03 0.00 91.76
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
sda1 0.69 33.21 48.54 129.62 773.23 1328.76 11.80 1.39 7.82 2.28 40.56
9. iostat – Execute Every x seconds (for y number of times)
To execute iostat every 2 seconds (until you press Ctl-C), do the following.$ iostat 2
Linux 2.6.32-100.28.5.el6.x86_64 (dev-db) 07/09/2011
avg-cpu: %user %nice %system %iowait %steal %idle
5.68 0.00 0.52 2.03 0.00 91.76
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 194.67 1096.39 1598.33 2719070584 3963891256
sda1 178.16 773.26 1328.79 1917688482 3295418672
sda2 16.51 323.11 269.54 801326878 668472584
sdb 371.22 945.74 1073.08 2345454041 2661251200
sdb1 371.22 945.72 1073.08 2345398577 2661251200
sdc 407.93 207.00 972.19 513366813 2411036564
sdc1 407.93 206.98 972.19 513311349 2411036564
..
To execute every 2 seconds for a total of 3 times, do the following.$ iostat 2 3
10. iostat – Display LVM statistic (and version)
To display the LVM statistics use option -N as shown below.$ iostat -N
To display the version of iostat, use -V. This will really display
the version information of sysstat, as iostat is part of sysstat
package.$ iostat -V
sysstat version 7.0.2
(C) Sebastien Godard
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