Disk activity is also monitored. High disk usage means that there will be a greater chance that an application
requesting data from disk will block until the disk is ready for that process
To see the disk activity
# sar -d
device: This is the disk, or disk partition, being measured. In Sun Solaris, you must translate this disk into a
physical disk by looking up the reported name in /etc/path_to_inst, and then cross-reference that information
to the entries in /dev/dsk. In Linux®, the major and minor numbers of the disk device are used
%busy: This is the percentage of time the device is being read from or written to.
avque: This is the average depth of the queue that is used to serialize disk activity. The higher the avque value,
the more blocking is occurring.
r+w/s, blks/s: This is disk activity per second in terms of read or write operations and disk blocks, respectively.
avwait: This is the average time (in milliseconds) that a disk read or write operation waits before it is performed.
avserv: This is the average time (in milliseconds) that a disk read or write operation takes to execute.
The -b argument shows information on buffers and the efficiency of using a buffer versus having to go to disk.
High process creation can lead to poor performance and is a sign that you might need to move some applications to another computer.
The -g, -p, and -w arguments show paging (swapping) activity.
High paging is a sign of memory starvation.
In particular, the -w argument shows the number of process switches:
A high number can mean too many things are running on the computer, which is spending more time switching
than working.
The -q argument shows the size of the run queue, which is the same as the load average for the time.
The -r argument shows free memory and swap space over time.
Measure CPU utilization during 5 secs one time.
sar -u 5 1
Measure CPU utilization during 60 secs 1440 times and write result in file sar.log.
sar -u -o sar.log 60 1440
To later review disk and tape activity from that period:
sar -d -f sar.log
vmstat to see the virtual memory statistics
iostat to see the input and output statistics
top
prtstat It is command line tool
sdtprocess It is GUI based tool
requesting data from disk will block until the disk is ready for that process
To see the disk activity
# sar -d
device: This is the disk, or disk partition, being measured. In Sun Solaris, you must translate this disk into a
physical disk by looking up the reported name in /etc/path_to_inst, and then cross-reference that information
to the entries in /dev/dsk. In Linux®, the major and minor numbers of the disk device are used
%busy: This is the percentage of time the device is being read from or written to.
avque: This is the average depth of the queue that is used to serialize disk activity. The higher the avque value,
the more blocking is occurring.
r+w/s, blks/s: This is disk activity per second in terms of read or write operations and disk blocks, respectively.
avwait: This is the average time (in milliseconds) that a disk read or write operation waits before it is performed.
avserv: This is the average time (in milliseconds) that a disk read or write operation takes to execute.
The -b argument shows information on buffers and the efficiency of using a buffer versus having to go to disk.
High process creation can lead to poor performance and is a sign that you might need to move some applications to another computer.
The -g, -p, and -w arguments show paging (swapping) activity.
High paging is a sign of memory starvation.
In particular, the -w argument shows the number of process switches:
A high number can mean too many things are running on the computer, which is spending more time switching
than working.
The -q argument shows the size of the run queue, which is the same as the load average for the time.
The -r argument shows free memory and swap space over time.
Measure CPU utilization during 5 secs one time.
sar -u 5 1
Measure CPU utilization during 60 secs 1440 times and write result in file sar.log.
sar -u -o sar.log 60 1440
To later review disk and tape activity from that period:
sar -d -f sar.log
vmstat to see the virtual memory statistics
iostat to see the input and output statistics
top
prtstat It is command line tool
sdtprocess It is GUI based tool
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