[DRBD-user] Re: drbd-0.7.5 on alpha, process stuck in D state after (simulated) disk failure

Nils Juergens ju at isf.rwth-aachen.de
Mon Dec 20 17:19:05 CET 2004

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Hello Todd,

Todd Denniston wrote:
> At least with the 0.6.X variants of DRBD, you could set drbd up to panic the
> kernel when the lower level device was lost ... sort of a fencing mechanism.
> It also guaranties all the services, heartbeat is configured for, move to
> the other node instead of hanging on the crippled node.

Yes, this is in 0.7.x, too, and i've given it some thought. This is also 
how other shared-storage systems work (at least netware 6 does, it 
abends on disk error, which is basically a panic()).

I'm aware of the fact that my setup is worthless if it can't survive the 
panic() case, so this may be a viable workaround.

However, I find the continue-as-diskless-client-method a lot more 
elegant, because it's a lot less intrusive for both the server processes 
and their respective clients. I also expect disk io-errors to occur more 
often than other faults, so I would really like to use the detatch mode, 
in wich, if I understand it correctly, all disk requests are served from 
the other nodes' harddrive.

And since we are still in the testing phase I would like to track down 
this (alleged) bug and maybe even give something back to the community 
(in form of a patch) :-)

But first, of course, I need someone to tell me that drbd should do what 
I expect and this is really a bug and not some sort of misunderstanding 
on my side.

thanks for your input,
Nils




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