disk wait mystery

[Erich Dollansky]

Hi,

On Wed, 30 Jan 2013 05:37:29 -0500
Brett Wynkoop <wynkoop at wynn.com> wrote:

> On Wed, 30 Jan 2013 10:39:37 +0100
> "Ronald Klop" <ronald-freebsd8 at klop.yi.org> wrote:
> 
> > On Wed, 30 Jan 2013 06:18:49 +0100, Brett Wynkoop <wynkoop at wynn.com>
> > wrote:
> > 
> > > Greeting-
> > >
> > > Can anyone figure out why a mainly idle bone with only 2 user
> > > shells via ssh running would have so much in disk wait?
> > >
> > > wynkoop at beaglebone:~ % !ps
> > > ps ax
> > > PID TT  STAT     TIME COMMAND
> > >   0  -  DLs   0:00.02 [kernel]
> > >   1  -  ILs   0:00.20 /sbin/init --
> > >   2  -  DL    0:00.00 [xpt_thrd]
> > >   3  -  DL    0:01.92 [task: mmc/sd card]
> > >   4  -  DL    0:00.01 [pagedaemon]
> > >   5  -  DL    0:00.00 [vmdaemon]
> > >   6  -  DL    0:00.00 [pagezero]
> > >   7  -  DL    0:00.02 [bufdaemon]
> > >   8  -  DL    0:00.02 [vnlru]
> > >   9  -  DL    0:00.10 [syncer]
> > >  10  -  RL   17:15.90 [idle]
> > >  11  -  WL    0:07.91 [intr]
> > >  12  -  DL    0:00.17 [geom]
> > >  13  -  DL    0:00.21 [yarrow]
> > >  14  -  DL    0:00.06 [softdepflush]
> > >  15  -  DL    0:00.15 [schedcpu]
> > > 106  -  DL    0:00.00 [md0]
> > > 410  -  Is    0:00.06 dhclient: cpsw0 [priv] (dhclient)
> > > 448  -  Is    0:00.07 dhclient: cpsw0 (dhclient)
> > > 449  -  Is    0:00.01 /sbin/devd
> > > 634  -  Is    0:00.04 /usr/sbin/sshd
> > > 638  -  Is    0:00.55 /usr/sbin/cron -s
> > > 682  -  Is    0:00.64 sshd: wynkoop [priv] (sshd)
> > > 685  -  S     0:00.29 sshd: wynkoop at pts/0 (sshd)
> > > 678 u0  Is+   0:00.19 /usr/libexec/getty std.9600 ttyu0
> > > 686  0  Ss    0:00.74 -csh (csh)
> > > 831  0  R+    0:00.16 ps ax
> > > wynkoop at beaglebone:~ %
> > >
> > > -Brett
> > >
> > 
> > Hi,
> > 
> > Maybe I missed a previous email, but you don't provide much
> > information for people to think about.
> > As a start you might show the 'disk wait' output.
> > 
> > Ronald.
> > 
> 
> Ronald-
> 
> From the ps man page:
>               D       Marks a process in disk (or other short term,
>               uninterruptible) wait.
> 
> 
> Note all the D entries in the above ps output.
> 
how I understand the system, I would say that these tasks are all
swapped out to disk.

Erich