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Overview of the vmstat Utility
Oracle Tips by Burleson Consulting
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The vmstat utility is the most common UNIX
monitoring utility, and it is found in the majority of UNIX dialects (vmstat
is called osview on IRIX). The vmstat utility displays various server
values over a given time interval. The vmstat utility is invoked from
the UNIX prompt, and it has several numeric parameters. The first
numeric argument to vmstat represents the time interval (expressed in
seconds) between server samples. The second argument specifies the
number of samples to be reported. In the example that follows, vmstat
is executed to take 5 samples at 2-second intervals:
L 5-1
Almost all UNIX servers have some version of
vmstat. Before we look at the details for this powerful utility, let's
explore the differences that you are likely to see.
Dialect Differences in vmstat
Because each hardware vendor writes their own
vmstat utility, there are significant differences in vmstat output.
The vmstat output is different depending on the dialect of UNIX, but
each dialect contains the important server metrics.
Because vendors have written their own versions
of the vmstat utility, it can be useful to consult the online UNIX
documentation to see the display differences. In UNIX, you can see
your documentation by invoking the man pages. The term man is
short for manual, and you can see the documentation for your
particular implementation of vmstat by entering man vmstat from
your UNIX prompt.
Following is a sample of vmstat output for the
four most popular dialects of UNIX. In each example, the important
metrics appear in bold.
vmstat for Solaris
In the Sun Solaris operating environment, the
output from vmstat will appear like this:
L 5-2
>vmstat 2 5
procs memory page
disk faults cpu
r b w swap free re mf pi po
s6 -- -- in sy
cs us sy id
0 0 0 2949744 988800 0 4 0 0
0 0 0 148
200 41 0 0 99
0 0 0 2874808 938960 27 247 0 1
0 0 0 196
434 64 1 2 98
0 0 0 2874808 938960 0 0 0 0
0 0 0 134
55 32 0 0 100
0 0 0 2874808 938960 0 0 0 0
0 0 0 143
114 39 0 0 100
0 0 0 2874808 938960 0 0 0 0
0 0 0 151
86 38 0 0 100
vmstat for Linux
In the Linux operating environment, the output
from vmstat will appear like this:
L 5-3
>vmstat 2 5
procs memory swap io system
cpu
r b w swpd free buff cache si
bi bo
in cs us sy id
1 0 0 140 90372 726988 26228 0
0 0
14 7 0 0 4
0 0 0 140 90372 726988 26228 0
0 2
103 11 0 0 100
0 0 0 140 90372 726988 26228 0
0 5
106 10 0 0 100
0 0 0 140 90372 726988 26228 0
0 0
101 11 0 0 100
0 0 0 140 90372 726988 26228 0
0 0
102 11 0 0 100
vmstat for AIX
In the IBM AIX operating environment, the
output from vmstat will appear like this:
L 5-4
>vmstat 2 5
kthr memory page faults cpu
----- ----------- ------------------------ ------------ -----------
r b avm fre re pi po fr sr cy in sy
cs us sy id wa
7 5 220214 141 0 0 0 42 53 0 1724 12381
2206 19 46 28 7
9 5 220933 195 0 0 1 216 290 0 1952 46118
2712 27 55 13 5
13 5 220646 452 0 0 1 33 54 0 2130 86185
3014 30 59 8 3
6 5 220228 672 0 0 0 0 0 0 1929 25068
2485 25 49 16 10
vmstat for HP/UX
In the Hewlett Packard HP/UX operating environment, the
output from vmstat will appear like this:
L 5-5
>vmstat 2 5
r b w avm free re at pi po
in sy
cs us sy id
1 0 0 70635 472855 10 5 2 0
2024 2859
398 4 1 96
1 0 0 74985 472819 9 0 1 0
1864 1820
322 0 0 100
0 0 0 83056 472819 2 0 0 0
1846 1684
302 0 0 100
0 0 0 81390 472819 0 0 0 0
1847 1571
288 0 0 100
0 0 0 78788 472819 0 0 0 0
1852 1608
291 0 0 100
Now that we have seen the different display
options for each dialect of vmstat, let's take a look at the data
items in vmstat and understand the common values that we can capture
in STATSPACK tables.
This is an excerpt from "Oracle9i
High Performance tuning with STATSPACK" by Oracle Press.
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