ffs snapshot lockup

[Kris Kennaway]

On Fri, Oct 06, 2006 at 10:39:50AM +0300, Kostik Belousov wrote:
> On Thu, Oct 05, 2006 at 10:01:07AM -0400, Vivek Khera wrote:
> > 
> > On Oct 5, 2006, at 4:30 AM, Kostik Belousov wrote:
> > 
> > >>
> > >>The network load was minimal at the time.  I had everyone log out and
> > >>close mail etc.
> > >>
> > >
> > >What were the symptoms of locked system ? Could you log in on  
> > >console, or
> > >do something at the shell prompt on console ?
> > 
> > Console was non-responsive.  This time dump locked doing /usr so  
> > pretty much anything you try to run will block.  When the lockup  
> > happens when dump is running on my home dir (/u/yertle1) partition,  
> > as long as you don't need that partition you can log in and run any  
> > programs you like.  I have a service account whose home dir is in / 
> > var and was able to login that time to that account.  No such luck  
> > this time since any activity pretty much uses /usr.
> > 
> > Ping was responding (our monitoring didn't complain it was down).
> > 
> > The only thing I could do was break to debugger on the console.
> > 
> This is very strange. You 3 instances of getty where just reading the
> tty input, and all suspectible processes (like sshd) are waiting on net
> events. No processes are blocked on the fs. One nfsd is serving the request,
> and dump is active.

To repeat something I said earlier: when creating a snapshot
(e.g. which dump -L does), the entire system may become unresponsive
untilk the snapshot completes, which can take many minutes.

How long are you waiting before pronouncing the system deadlocked?

What does ^T on the console (e.g. when trying to log in), show you?

Kris

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