Re: [PATCH 0/7] dlm: overview

David Lang
2005-04-29T00:34:11Z

On Thu, 28 Apr 2005, Lars Marowsky-Bree wrote:

> On 2005-04-27T18:38:18, Daniel Phillips <phillips@istop.com> wrote:
>
>> Uuids's at this level are inherently bogus, unless of course you have more
>> than 2**32 cluster nodes. I don't know about you, but I do not have even
>> half that many nodes over here.
>
> This is not quite the argument. With that argument, 16 bit would be
> fine. And even then, I'd call you guilty of causing my lights to flicker
> ;-)
>
> The argument about UUIDs goes a bit beyond that: No admin needed to
> assign them; they can stay the same even if clusters/clusters merge (in
> theory); they can be used for inter-cluster addressing too, because they
> aren't just unique within a single cluster (think clusters of clusters,
> grids etc, whatever the topology), and finally, UUID is a big enough
> blob to put all other identifiers in, be it a two bit node id, a
> nodename, 32bit IPv4 address or a 128bit IPv6.
>
> This piece is important. It defines one of the fundamental objects in
> the API.
>
> I recommend you read up on the discussions on the OCF list on this; this
> has probably been one of the hottest arguments.

how is this UUID that doesn't need to be touched by an admin, and will
always work in all possible networks (including insane things like backup
servers configured with the same name and IP address as the primary with
NAT between them to allow them to communicate) generated?

there are a lot of software packages out there that could make use of
this.

David Lang