Solving Common Replication Conflicts - Netscape DIRECTORY SERVER 6.01 - ADMINISTRATOR Administrator's Manual

Solving Common Replication Conflicts

Multi-master replication uses a loose consistency replication model. This means
that the same entries can be changed on different servers. When replication occurs
between the two servers, the conflicting changes need to be resolved. Mostly,
resolution occurs automatically, based on the timestamp associated with the
change on each server. The most recent change takes precedence.
However, there are some cases where change conflicts require manual intervention
in order to reach a resolution. Entries that have a change conflict that cannot be
resolved automatically by the replication process, contain a conflict marker
attribute
attribute which makes it simple to search for entries that contain this attribute.
For example, you could use the following
prompt% ldapsearch -D adminDN -w passwd -b "dc=example,dc=com"
"nsds5ReplConflict=*"
For performance reasons, if you find that you have many conflicting entries every
day, you may want to index the
indexing, refer to Chapter 10, "Managing Indexes."
This section contains the procedures for the following conflict resolution
procedures:
• Solving Naming Conflicts
• Solving Orphan Entry Conflicts
• Solving Potential Interoperability Problems
Solving Naming Conflicts
When two entries are created with the same DN on different servers, during
replication, the automatic conflict resolution procedure renames the last entry
created by including the entry's unique identifier in the DN. Every directory entry
includes a unique identifier given by the operational attribute
naming conflict occurs, this unique ID is appended to the non-unique DN.
For example, the entry
Server A at time t1, and on Server B at time t2, where t2 is greater (or later) than t1.
After replication, Server A and Server B both hold the following entries:
•
uid=adamss,ou=people,dc=example,dc=com
. The
nsds5ReplConflict
uid=adamss,ou=people,dc=example,dc=com
nsdsReplConflict
ldapsearch
nsds5ReplConflict
(created at time t1)
Chapter 8
Solving Common Replication Conflicts
attribute is an operational
command:
attribute. For information on
. When a
nsuniqueid
is created on
Managing Replication 323