na.iostat manual page
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NAME

na.iostat - Input/Output statistics

DESCRIPTION

na.iostat returns information about the CPU, disk, and TTY activity on the host where the agent is running. By default, the agent reads /vmunix to get the kernel namelist.

A reporting interval is specified by the management application. If a reporting interval is not specified, the agent will send a report every 30 seconds.

ATTRIBUTES

na.iostat has one attribute table, disk, and two attribute groups, cpu and tty.

The disk table reports statistics about the system's disks. The key is the name. The attributes in the table are:

name - name of the disk (string)
mbytes - (SunOS 4.x only) number of megabytes transferred since boot (counter)
xfers - (SunOS 4.x only) number of disk transfers since boot (counter)
reads - number of reads since boot (counter) writes - number of writes since boot (counter) seeks - (SunOS 4.x only) number of seeks since boot (counter)
activeT - (SunOS 4.x only) seconds active since boot (counter)
xferT - (SunOS 4.x only) seconds spent transferring data since boot (counter)
seekT - (SunOS 4.x only) seconds spent seeking since boot (counter)
%xferT - (SunOS 4.x only) percent of active time spent transferring data (gauge)
avgXferT - (SunOS 4.x only) average transfer time, in milliseconds (gauge)
avgSeekT - (SunOS 4.x only) average seek time, in milliseconds (gauge)
kbps - (SunOS 4.x only) transfer rate, in Kbytes per second (gauge)
kreads - (SunOS 5.x only) number of Kbytes read per second (float)
kwrites - (SunOS 5.x only) number of Kbytes written per

second (float)
svcwait - (SunOS 5.x only) average number of transactions waiting for service (float)
acttrans - (SunOS 5.x only) average number of transactions actively being serviced (float)
svctime - (SunOS 5.x only) average service time in milliseconds (float)
%wait - (SunOS 5.x only) percent of time there are transactions waiting for service (float)
%busy - (SunOS 5.x only) percent of time the disk is busy (float)

The cpu group reports statistics about the CPU utilization.

user - number of ticks spent running user jobs since boot (counter)
nice - number of clock ticks spent in nice mode since boot (counter)
sys - number of clock ticks spent in system mode since boot (counter)
idle - number of clock ticks spent idle since boot (counter)

The tty group reports statistics about tty input and output.

tty_in - number of characters read since boot (counter) tty_out - number of characters written since boot (counter)

OPTIONS

The SunOS 4.x version accepts one option: the name of an alternate file to use to get the kernel namelist.

The SunOS 5.x version has no options.

ERRORS

can't read kernel memory
The agent uid does not have permission to read kernel memory, /dev/kmem. Run the agent as root (default case if agent started by inetd (1M) ), or give read permission to the uid the agent is running under. The error message can also occur if the agent can't find or read the file containing the kernel namelist.

NOTES

Milliseconds per average seek is an approximation based on the disk (not the controller) transfer rate. Therefore, the seek time will be overestimated in systems with slower controllers.

Not all controllers report all data. In particular, number of seeks is unavailable for SCSI disks.

The SunOS 4.1.x kernel keeps statistics for up to 32 drives. However, the kernel as shipped only reserves space for statistics for 10 drives. To increase the space, change the constant DK_NDRIVE in /usr/include/sys/dk.h to any value up to 32. After you make the change, recompile your kernel (you must have SunOS kernel sources) and reboot with the new kernel. If you do not have kernel sources, then you cannot get statistics for more than 10 drives.


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