Re: requesting vinum help

On Thursday, 27 November 2003 at  0:13:09 -0600, Cosmin Stroe wrote:
> On Thu, 27 Nov 2003, Greg 'groggy' Lehey wrote:
>
>> On Wednesday, 26 November 2003 at 12:04:52 -0600, Cosmin Stroe wrote:
>>>
>>> I am using vinum atm, and I am having serious problems with it.  After
>>> about 16 hrs of writing data to a vinum volume via NFS at a constant data
>>> stream of 200k/sec and reading at 400k/sec at the same time, the whole
>>> machine just freezes, hard.  The only thing I can do is reboot.  This
>>> behavior appears in 4.8 and 5-CURRENT.  I have no indication of what is
>>> wrong, or how to go about finding it out.  The problem is either with NFS
>>> or Vinum, and I'm leaning towards Vinum (because of the failure in both
>>> -STABLE and -CURRENT).
>>>
>>> I'm not the kind of person that relies on other people, and I like to fix
>>> my own problems, but this is a problem which I cannot fix at this time.
>>> So, I'm planning to look through the code of vinum and start messing with
>>> it to figure out how it works and how to debug it.
>>
>> This is unlikely to get you very far.  Some more details (offline if
>> you prefer) would be handy, but as you say, you can't even be sure
>> that it's Vinum.  The best thing would be to get the system into the
>> kernel debugger at the point of freeze, if that's possible, and try to
>> work out what has happened.
>
> Quick question: If this is a software problem with vinum, there
> should be no way it can hard lock a machine.  Is this assumption
> correct ?

Heh.  Depends on what you mean by a software problem.  The right kind
of software problem anywhere can hard lock machines :-(

> I should be able to invoke the kernel debugger by pressing the
> hotkey (ctrl+alt+esc) while the machine is locked and get a
> backtrace (altho i'd be in an ISR servicing the hotkey, so i'm not
> sure it'd do much good).

It would enable you to look around and figure out what's gone wrong.

> Any special suggestions on debugging this kind of freezing problem ?
> The hardware has been tested and it's good (CPU,RAM,HDs). (some kind
> of watchdog in software ??)

I have some debugging help in Vinum which will log what's going on,
but it doesn't help much in the case of a hard freeze.  It could be a
deadlock.  Do you have swap on Vinum?

Greg
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