dump is stuck

[Danny Braniss]

> In message <20050128144733.GA91982 at green.homeunix.org>, Brian Fundakowski Feldman writes:
> >On Fri, Jan 28, 2005 at 09:08:54AM +0200, Danny Braniss wrote:
> >> hi,
> >> 	while running 'dump 0f - /dist | restore rf -'
> >> the dump proc. got stuck, it seems it's waiting on some lock:
> >> 
> >> UID   PID  PPID CPU PRI NI   VSZ  RSS MWCHAN STAT  TT       TIME COMMAND
> >> 
> >>  0 30924 30922   0   4  0  3396 2852 sbwait T     p1    1:00.88 dump: 
> >> /dev/amrd0s3h: ...
> >>  0 30925 30924   1  -8  0  3268 2784 physrd TL    p1    0:53.84 dump 0f - 
> >> /dist (dump)
> >>  0 30926 30924   1  20  0  3268 2784 pause  T     p1    0:53.69 dump 0f - 
> >> /dist (dump)
> >>  0 30927 30924   1  20  0  3268 2784 pause  T     p1    0:54.12 dump 0f - 
> >> /dist (dump)
> >> 
> >> (this is  5.3-STABLE, cvs'ed about a week ago, and it's a SMP system).
> >> how can i find which lock? or who is holding it?
> >
> >Is the one in physrd not actually reading anything from the disk right
> >now?  I would suspect that should be how you really determine if it's
> >hung or not.  You should be able to see how long it's been waiting
> >and how long it's due to wait still, using kgdb.
> 
> Check also with gstat(8) if there is I/O activity going on and/or if any
> I/O requests are stuck.

it's stuck. i.e. not doing anything. i've been monitoring it via
iostat, and nothing is moving, nada, the machine is very idle :-(
i managed only once to do a dump -L -C32 -0f - /dist | restore -rf -
and it finished ok. I have tried it several times since, and it gets stuck
(at different places!)
im now trying just dump - without the restore, lets see if it works, but
i'm willing to bet it will get stuck.

danny