scan rate and "w" output from vmstat
Georgios Magklaras
georgios at biotek.uio.no
Tue Mar 8 05:09:31 UTC 2011
On 03/07/2011 06:05 PM, travel NJ wrote:
> Hi,
>
> I am in the process of converting a script for gathering system info in
> Solaris to be used in Linux.
>
> I noticed RedHat 5.5 does not have the "w" output from vmstat even the
> manpage indicates that it exists
>
> [sysadm at unix ~]$ vmstat 5 5
> procs memory swap io system
> cpu
> r b swpd free buff cache si so bi bo in cs us sy id
> wa
> 1 0 0 2492644 124640 1039360 0 0 0 0 0 0 0 1
> 0 0
> 1 0 0 2492644 124640 1039360 0 0 0 14 103 188 25 0
> 75 0
> 1 0 0 2492644 124640 1039360 0 0 0 0 102 191 25 0
> 75 0
> 1 0 0 2492644 124640 1039360 0 0 0 30 108 189 25 0
> 73 2
> excerpt from man
>
> FIELD DESCRIPTIONS
> Procs
> r: The number of processes waiting for run time.
> b: The number of processes in uninterruptable sleep.
> w: The number of processes swapped out but otherwise runnable. This
> field is calculated, but Linux never desperation swaps.
> In addition, it does not have the "sr" as similar to Solaris's vmstat. I do
> know that many of the info are stalled in /proc, but is /proc/vmstat the
> only location I can get the scanrate ? will it be pgscan_kswapd_high?
>
> thanks
The vmstat manpage of RHEL 5.6 does NOT mention the w column. I have
checked it out:
FIELD DESCRIPTION FOR VM MODE
Procs
r: The number of processes waiting for run time.
b: The number of processes in uninterruptible sleep.
Memory
swpd: the amount of virtual memory used.
The w column on Unix land vmstat refers to the number of procs that are
runnable but swapped out of RAM. vmstat offers only the number of
bytes/kb/mb swapped.
Redhat recommends 'dstat' as a replacement for vmstat. Do a
yum -y install dstat
on your RHEL box and then play with something like:
dstat -vms
If I were you, I would concentrate on r, b and the free swapped space.
What matters is not so much how many procs are swapped but the rate of
forking, the b, r and the free swap that you have. This could give you
more meaningful stats in a cross-platform overloaded system monitoring
scenario
GM
--
--
George Magklaras
Senior Systems Engineer/IT Manager
Biotek Center, University of Oslo
EMBnet TMPC Chair
http://folk.uio.no/georgios
Tel: +47 22840535
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