Introduction to the AIX iostat command

Introduction to the AIX iostat command 1. determine disk usage $ iostat-T 2 10 System configuration: lcpu = 8 drives = 29 paths = 52 vdisks = 0tty: tin tout avg-cpu: % user % sys % idle % iowait time 0.0 377.0 77.6 6.1 16.2 11: 35: 45 Disks: % tm_act Kbps tps Kb_read Kb_wrtn timehdisk5 0.1 78.0 6080.0 439.0 11: 35: 45hdisk4 79.5 11856.5 453.5 23564 149 11: 35: 45hdisk6 19.0 1664.0 13.0 0 11:35:45 $ % tm_act percentage of time when a physical disk is active KBPS the total amount of data transmitted on a disk (Read or write) tps the number of I/o transfers per second for a physical disk Kb_read the total amount of data read from the disk Kb_wrtn the total amount of data written to the disk if the % tm_act field shows that the disk is very busy, in addition, if the Kbps field shows continuous massive data transmission, consider spreading data across multiple disks. This command supports dynamic configuration changes. If the configuration changes are detected, the iostat report issues a warning and updates the latest system configuration. Here, % tm_act refers to the activity time, and kbps refers to the sum of all Kb_read and Kb_wrtn in the statistical time divided by the time value, that is, the number of bytes transmitted per second. If % tm_act is usually over 70% but only has a low Kbps, the system may have a large number of LV fragments or file fragments. when both are high, the system will be normal. Tps indicates the number of I/O operations per second. Different disk systems have different numbers of I/O operations. If the activity rate of a disk exceeds 70%, you can transfer part of the disk activity pressure to another disk, or use multiple disk drives to expand the I/O pressure to achieve higher performance. $ Iostat-D hdisk0 (View A disk) System configuration: lcpu = 8 drives = 29 paths = 52 vdisks = 0hdisk0 xfer: % tm_act bps tps bread bwrtn 4.6 58.3 K 8.8 16.5 K 41.9 K read: rps avgserv minserv maxserv timeouts fails 3.5 5.8 0.3 67.8 0 0 write: wps avgserv minserv maxserv timeouts fails 5.3 11.2 0.6 114.9 0 0 queue: avgtime mintime maxtime avgwqsz avgsqsz sqfull 136.8 0.0 388.4 0.2 0.0 3.8 ----------------------- ------------------------------------------------------- If you use a device that enables multi-path I/O [multi-path input-output (MPIO)], you can use the iostat-m command to display statistics of each related path. $ Iostat-m-D hdisk6System configuration: lcpu = 8 drives = 29 paths = 52 vdisks = 0hdisk6 xfer: % tm_act bps tps bread bwrtn 3.4 286.7 K 28.6 K 285.3 K read: rps avgserv minserv maxserv timeouts fails 28.5 1.9 0.1 0 0 write: wps avgserv minserv maxserv timeouts fails 383.4 0.1 4.5 0.2 0 0 queue: avgtime mintime maxtime avgwqsz avgsqsz sqfull 0.9 0.0 326.3 0.0 0.0 21.0Path1 xfer: % tm_act bps tps brea D bwrtn 3.4 286.7 K 28.6 285.3 K 1.4KPath0 xfer: % tm_act bps tps bread bwrtn 0.0 0.0 0.0 0.0 limit 2. determine CPU usage $ iostat 2 System configuration: lcpu = 8 drives = 29 paths = 52 vdisks = 0tty: tin tout avg-cpu: % user % sys % idle % iowait 0.0 354.5 79.4 4.6 15.9 0. 0 ............ total number of characters read by tin system from all ttys tout total number of characters written to all ttys % user in user mode Percentage of CPU usage executed % sys percentage of CPU usage executed in kernel mode % percentage of idle CPU idle time, the system does not have the percentage of unresolved disk I/O Requests % iowait CPU idle time. During this period, the system has unresolved disk I/O Requests % physc's percentage of physical CPU consumption, the % entc consumption Percentage of allocated capacity is displayed only in the partition where the shared processor is running, and only 3 is displayed in the partition where the shared processor is running. asynchronous IO $ iostat-ASystem configuration: lcpu = 8 drives = 29 paths = 52 vdisks = 0aio: avgc avfc maxg maif maxr 0 0 0 22 4096 avgc within the specified interval, average global non-fast path AIO request count per second avfc specifies the maximum number of requests in the global AIO fast path per second maxg since the last value St path AIO request count maxf since the last value, the maximum fast path request count maxr allows the maximum AIO requests. This is the maxreqs attribute of the AIO Device 4. determine the adapter utilization $ iostat-aSystem configuration: lcpu = 8 drives = 29 paths = 52 vdisks = 0tty: tin tout avg-cpu: % user % sys % idle % iowait 0.0 12.6 13.5 2.2 83.4 0.8 Adapter: Kbps tps Kb_read Kb_wrtnfcs0 0.0 0.0 180 0 Disks: % tm_act Kbps tps Kb_read limit 0.0 0.0 0.0 0.0 0 0hdisk9 0.0 0.0 0.0 0 0hdisk18 0.0 0.0 0.0 0 0hdisk5 0.0 0.0 0.0 0 0hdisk11 0.0 0.0 0.0 0.0 0 0hdisk12 0.0 0.0 0.0 0 0hdisk16 0.0 0.0 0.0 0 0hdisk13 0.0 0.0 0.0 0 0hdisk14 0.0 0.0 0.0 0 0hdisk19 0.0 0.0 0.0 0 0hdisk4 0.0 0.0 0.0 0.0 0.0 0.0 0hdisk20 180 0.0 0 0hdisk15 0.0 0.0 0.0 0 0hdisk22 0.0 0.0 0.0 0 0hdisk24 0.0 0.0 0.0 0 0hdisk17 0.0 0.0 0.0 00hdisk6 0.0 0.0 0 0hdisk21 0.0 0.0 0.0 0 0hdisk23 0.0 0.0 0.0 0 0hdisk26 0.0 0.0 0.0 0 0hdisk27 0.0 0.0 0.0 0 0 Adapter: kbps tps Kb_read limit 1037.2 24.0 853190413 2792786844 Disks: % tm_act Kbps tps Kb_read Kb_wrtnhdisk2 0.0 0.0 0.0 2.9 0 0hdisk1 43.1 5.9 7601140 4.6 57.0 8.8 56471864 3.6 143758376hdisk3 937.2 9.4 789117409 2505270092 Adapter: kbps tps Kb_read Kb_wrtnide0 0.0 0.0 0 0 Disks: % tm_act Kbps tps Kb_read Kb_wrtncd0 0.0 0.0 0.0 0 0 Adapter: Kbps tps Kb_read Kb_wrtnfcs1 1753.6 141.4 5991841616 172643922 Disks: % tm_act Kbps tps Kb_read limit 0.0 0.0 0.0 0.0 0 0hdisk9 0.0 0.0 0.0 0 0hdisk18 0.0 0.0 7.9 0 0hdisk5 761.6 69.1 2654793648 0.0 0.0 0.0 0.0 58.5 0.2 205481199 0hdisk12 0.0 0.0 0 0hdisk16 0.0 59.9 0.3 210289843 108792hdisk13 0.0 0.0 0.0 0 0hdisk14 0.0 0.0 0.0 0 0hdisk19 0.0 0.0 0.0 0 0hdisk4 5.8 593.5 43.2 1941265217 0hdisk15 0.0 0.0 0.0 0 0hdisk15 0.0 0.0 0.0 0hdisk22 0.0 0.0 0.0 0 0hdisk24 0.0 0.0 0.0 0 0hdisk17 0.0 0.0 0.0 0 0hdisk6 3.4 280.2 28.6 980011709 0.0 0hdisk25 0.0 0.0 0 0hdisk23 0.0 0.0 0.0 0.0 0 0hdisk26 0.0 0.0 0.0 0 0hdisk27 0.0 0.0 0.0 0 0