Re: Comments on ldup-replica-req-00.txt

["John Merrells" <merrells@xxxxxxxxxxxx>]

Alan Lloyd wrote:

>         The mechanism of stating UIDs, DNs (where names are modified)
> and such things are easy to say and write down in an RFC - now what.
> operationally it will hit walls and system robustness will be demaned
> from high end directory systems that run banks, telephone
> infrastructures, CAs and online services and military applications.

How else do you replicate the change?

>         As said the image that a directory is a mail address book that
> must be replicated is still out there - and some simple tagging system
> may be all thats needed for these -

We may not use tagging.

>         If directories are to be a disciplined, robust infrastucture we
> really have to watch tagging and transaction mechanisms - If one cannot
> scale it and inteconnect it reliably - dont bother.

Yes, our goal is interoperability and a requirement is scalability.

>         and what happens if a DSA has a clock set to tomorow and its
> updated at the same time - differently -  in the actual time + - a
> second,  as a  DSA with its clock set to today ?

You don't have to use time for conflict resolution.

> [snip... icl]
>         X.500 permits inconsistencies for this reason - ie clock
> synchronisation over the planet is hard - therefore a requirement to
> grab the "logical master entry" is provided in the protocol options.

You don't have to use time for conflict resolution.There could be multiple masters, how do you know which holds theone true
value.

>         So the replication process really does not want to impose
> exponential loads on this infrastructure just trying to keep every thing
> consistent.

Scalable architecture is a requirement.

> > Lovely, but customers are asking for replicated directory services.
> >
>         yes we know,  but that IMHO is because the "directory" experts
> have been  preaching that due to products distributed operations too
> well or at all (LDAP) and the LDAP theme of doing replication now.  But
> then reality hits,  as it always does - scaleability and interopration
> and information consistency are now comming to the fore.
>
>         Its going to be an interesting world when all the "replicate
> hypers" suddenly realise that all they are doing is casting a system
> which is unscaleable by nature and when they want to eventually
> interconnect for distributed operations - what a mess they will be in.

Yes, interoperability is the goal, scalability a requirement.

>         Distribution gets the naming and the knowledge and domain based
> access control policies in place (and the distributed performance issues
> resolved) that enable directory system scaling.

We still need Replication and LDUP is the Replication working group.

> Replication just
> provides one with a "copy" of the inteconnection and performance
> problems as described that have not been fixed.

Customers require replicated directory services.

John

--
John Merrells
Netscape Communications
Directory Server
Software Engineer

http://people.netscape.com/merrells