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iostat(1) [ultrix man page]

iostat(1)						      General Commands Manual							 iostat(1)

Name
       iostat - report I/O statistics

Syntax
       iostat [ -c ] [ -t ] [ disknames ] [ interval ] [ count ]

Description
       The  command  reports  I/O  statistics for terminals, disks and cpus.  For terminals the number of input and output characters are counted.
       For disks the number of 512 byte blocks per second and number of transfers per second are displayed.  For cpus, it provides the	percentage
       of  time  the system has spent in user mode, in user mode running low priority (niced) processes, in system mode, and idling.  On multipro-
       cessor systems these cpu statistics represent a cumulative summary of all the cpus.

       The optional disknames argument causes disk statistics to be displayed for the specified disks.	If this argument  is  not  specified  then
       disk statistics will be displayed for the first 3 disks only.

       The  optional interval argument causes to report once each interval seconds.  The first report is for all time since a reboot and each sub-
       sequent report is for the last interval only.

       The optional count argument restricts the number of reports.

Options
       -c   Displays the percentage of time each cpu spent in user mode, running low priority (nice'd) processes, in system mode, and idling.

       -t   Displays the number of characters read from and written to terminals.

Examples
       This example will cause cpu and disk statistics for the 5 disks ra0, ra1, ra2, ra3, and ra4.
	    iostat ra0 ra1 ra2 ra3 ra4
       This example will cause cpu, terminal, and disk statistics for ra0 to be displayed and updated every 2 seconds.
	    iostat -t ra0 2

Files
See Also
       vmstat(1), cpustat(1)

																	 iostat(1)

Check Out this Related Man Page

IOSTAT(1M)																IOSTAT(1M)

NAME
iostat - report I/O statistics SYNOPSIS
iostat [ option ] ... [ interval [ count ] ] DESCRIPTION
Iostat delves into the system and reports certain statistics kept about input-output activity. Information is kept about up to three dif- ferent disks (RF, RK, RP) and about typewriters. For each disk, IO completions and number of words transferred are counted; for typewrit- ers collectively, the number of input and output characters are counted. Also, each sixtieth of a second, the state of each disk is exam- ined and a tally is made if the disk is active. The tally goes into one of four categories, depending on whether the system is executing in user mode, in `nice' (background) user mode, in system mode, or idle. From all these numbers and from the known transfer rates of the devices it is possible to determine information such as the degree of IO overlap and average seek times for each device. The optional interval argument causes iostat to report once each interval seconds. The first report is for all time since a reboot and each subsequent report is for the last interval only. The optional count argument restricts the number of reports. With no option argument iostat reports for each disk the number of transfers per minute, the milliseconds per average seek, and the mil- liseconds per data transfer exclusive of seek time. It also gives the percentage of time the system has spend in each of the four cate- gories mentioned above. The following options are available: -t Report the number of characters of terminal IO per second as well. -i Report the percentage of time spend in each of the four categories mentioned above, the percentage of time each disk was active (seeking or transferring), the percentage of time any disk was active, and the percentage of time spent in `IO wait:' idle, but with a disk active. -s Report the raw timing information: 32 numbers indicating the percentage of time spent in each of the possible configurations of 4 system states and 8 IO states (3 disks each active or not). -b Report on the usage of IO buffers. FILES
/dev/mem, /unix IOSTAT(1M)
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