I take it this implementation of DBD is different than
the one included in the 2.2.x
kernels? That one didn't do its own mirroring, and
would block on IO when the secondary
node died. Didn't help that it required MD-RAID to do
mirroring.. which of course is NOT
network aware..
I'm new to the linux-ha realm, so forgive me if I ask
questions which have been asked time and
again.. but.. is there a particular reason that almost
every 'network block device' type scenario
is built for a 2 node cluster? Is there some reason
why people would NOT want to have more
than two nodes in a cluster? I'm just wondering
whether I'm attempting to cause more problems
for myself than I really need.
Thanks!
Zackary D. Deems
Unix Systems Administrator
Virginia Dept. of Education
---------------------------------------
Actually, there is a storage system that supports > 2
nodes. The
distributed block device (DBD) module in the CEnsemble
toolkit
supports just about any number of nodes. The DBD is
like DRDB except
that it allows any number of clients to access any
number of logical
disks that are replicated (with 2-way redundancy) on
any number of
storage servers. It includes a distributed lock
manager, and we are
actively working on integrating the GFS+DBD+DLM to
produce a full
clustered file system.
You can get CEnsemble from www.censemble.com. I`m
preparing a
release of DBD that includes the (previously missing)
kernel driver
and is pretty stable. It will be available in the
next couple of
weeks. Please contact me if you would like to try a
pre-release of
the software.
--Mark
Lars Marowsky-Bree wrote:
>
> On 2000-11-21T15:45:42,
> "Zackary D. Deems" <zdeems@example.com> said:
>
> > Has anyone come up with a way to use DRBD on more
than 2 nodes,
> > mirroring the same partition(s)?
>
> No.
>
> We are accepting patches though ;-)
>
> You _can_ use stacked drbd`s, but this may prove to
be not what you want. I
> also don`t want to think about the complexity this
introduces...
>
> > If not, is there another product which is meant to
cater more toward the
> > 3+ node cluster configuration?
>
> No.
>
> I am not even sure whether EMC^2 RDF does cater to
more than two nodes.
>
> You may wish to investigate a shared storage
solution - using shared SCSI or
> Fibre Channel - and using GFS on top of it, a
special filesystem to allow
> multiple nodes to access this concurrently.
(
http://www.globalfilesystem.org/)
>
> What are you trying to achieve? Maybe the
linux-ha@example.com list is a good place
> to discuss the general design of your project.
>
> Sincerely,
> Lars Marowsky-Bre <lmb@example.com>
> Development HA
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