Sun Solaris Displaying Disk Utilization Information (iostat n)

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Displaying Disk Utilization Information (iostat n)
Use the iostat command to report statistics about disk input and output, and produces measures of throughput, utilization, queue lengths, transaction rates, and service time. For a detailed description of this command, refer to iostat(1M).
How to Display Disk Utilization Information (iostat)
You can display disk utilization information by using the iostat command with a time interval in seconds.

$ iostat 5 tty fd0 sd3 nfs1 nfs31 cpu tin tout kps tps serv kps tps serv kps tps serv kps tps serv us sy wt id 0 1 0 0 410 3 0 29 0 0 9 3 0 47 4 2 0 94

The first line of output shows the statistics since the last time the system was booted. Each subsequent line shows the interval statistics. The default is to show statistics for the terminal (tty), disks (fd and sd), and CPU (cpu).
The following table describes the fields in the iostat command output.
Table 1 Output From the iostat n Command

Device Type	Field Name	Description
Terminal
	tin	Number of characters in the terminal input queue
	tout	Number of characters in the terminal output queue
Disk
	bps	Blocks per second
	tps	Transactions per second
	serv	Average service time, in milliseconds
CPU
	us	In user mode
	sy	In system mode
	wt	Waiting for I/O
	id	Idle

Example—Displaying Disk Utilization Information

The following example shows disk statistics that were gathered every five seconds.

$ iostat 5 tty sd0 sd6 nfs1 nfs49 cpu tin tout kps tps serv kps tps serv kps tps serv kps tps serv us sy wt id 0 0 1 0 49 0 0 0 0 0 0 0 0 15 0 0 0 100 0 47 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 0 16 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 0 16 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 0 16 44 6 132 0 0 0 0 0 0 0 0 0 0 0 1 99 0 16 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 0 16 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 0 16 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 0 16 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 0 16 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 0 16 3 1 23 0 0 0 0 0 0 0 0 0 0 0 1 99 0 16 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 0 16 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 0 16 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100

How to Display Extended Disk Statistics (iostat -xtc)
Run the iostat -xtc command to get extended disk statistics.

$ iostat -xtc extended device statistics tty cpu device r/s w/s kr/s kw/s wait actv svc_t %w %b tin tout us sy wt id fd0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 0 0 0 0 0 100 sd0 0.0 0.0 0.4 0.4 0.0 0.0 49.5 0 0 sd6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 nfs1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 nfs49 0.0 0.0 0.0 0.0 0.0 0.0 15.1 0 0 nfs53 0.0 0.0 0.4 0.0 0.0 0.0 24.5 0 0 nfs54 0.0 0.0 0.0 0.0 0.0 0.0 6.3 0 0 nfs55 0.0 0.0 0.0 0.0 0.0 0.0 4.9 0 0

The iostat -xtc command displays a line of output for each disk. The output fields are described in the following table.
Table 2 Output From the iostat -xtc Command

Field Name	Description
r/s	Reads per second
w/s	Writes per second
kr/s	Kbytes read per second
kw/s	Kbytes written per second
wait	Average number of transactions that are waiting for service (queue length)
actv	Average number of transactions that are actively being serviced
svc_t	Average service time, in milliseconds
%w	Percentage of time that the queue is not empty
%b	Percentage of time that the disk is busy