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@(#)iostat.8 6.8 (Berkeley) 4/24/91
iostat [ -c count ] [ -M core ] [ -N system ] [ -w wait ] [ drives ]
The options are as follows:
-c Repeat the display count times. The first display is for the time since a reboot and each subsequent report is for the time period since the last display. If no wait interval is specified, the default is 1 second.
-M Extract values associated with the name list from the specified core instead of the default ``/dev/kmem''.
-N Extract the name list from the specified system instead of the default ``/netbsd''.
-w Pause wait seconds between each display. If no repeat count is specified, the default is infinity.
Iostat displays its information in the following format:
tty
tin characters read from terminals tout characters written to terminals
disks Disk operations (this field is system dependent). The header of the field is the disk name and unit number. If more than four disk drives are configured in the system, iostat displays only the first four drives. To force iostat to display specific drives, their names may be supplied on the command line.
sps sectors transferred per second tps transfers per second msps milliseconds per average seek (including implied seeks and rotational latency)
cpu
us % of cpu time in user mode ni % of cpu time in user mode running niced processes sy % of cpu time in system mode id % of cpu time in idle mode
Indexes created Sun Oct 19 18:09:56 GMT 2025