[Drbd-dev] Re: [Linux-ha-dev] [RFC] (CRM and) DRBD (0.8) states and transistions, recovery strategies

Lars Marowsky-Bree lmb at suse.de
Sat Sep 25 10:54:28 CEST 2004

On 2004-09-25T01:04:57,
   Lars Ellenberg <Lars.Ellenberg at linbit.com> said:

> > I don't see any difference here between meta-data and backing store
> > loss, actually, that complicates things unnecessarily.
> well, DRBD needs to make a difference, because they meta-data storage
> and data storage may be physically different devices, and therefore can
> fail independently. (ok, single blocks can fail on the same physical
> storage independently, too, but this is an other thing)

The point I was trying to make is that meta-data loss and backing
storage loss can essentially be mapped to a generic local IO failure.

The special case where we only loss access to the backing store and not
to the meta-data allows us to set a flag there (for whatever use it may
be the next time we compare GCs), but then it amounts to the same: Loss
of the local storage.

I don't see any benefit in keeping the two as distinct failure modes...

    Lars Marowsky-Brée <lmb at suse.de>

High Availability & Clustering
SUSE Labs, Research and Development
SUSE LINUX AG - A Novell company

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