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

["John Merrells" <merrells@xxxxxxxxxxxx>]

Alan Lloyd wrote:

> It seems from the requirements text that the client software replicates
> by reading one server and then passing that to another.

I'm not sure how you managed to derive this from the text.  I see nomention of a client maintaining replica consistency between
two servers.

> In transferring many objects/entries over LDAP the connection may fail
> so a recovery point is needed. X.500 DISP is an atomic operation and
> implementations must ensure that a single DISP pdu works or does not. In
> the LDAP case - what are the recovery steps - are DIT locking mechanisms
> required.

The architecture draft(s) will have to address this reliability issue.  It couldinvolve DIT/subtree locking mechanisms, and
transactions.

> Also DAP has a control which can select master or copy information. Will
> this be added to LDAP.

No one's mentioned it so far.  Somehow I doubt it.

> Is the LDAP for replication protocol likely to be employed between
> servers in a bi- directional fashion to deal with replication
>
> In the first case looping may happen in multimasters unless attribute
> value checking is done .

Depends if you replicate attribute values or change operations.  In eithercase an increasing tag value is applied so that
updates propagate no further
than required.

> Are there issues with replica - incomplete entries

Er.. We intend to support both fractional and partial replicas.  That's an
entry filter, and an attribute filter.

John

--
John Merrells
Netscape Communications
Directory Server
Software Engineer

http://people.netscape.com/merrells