Red Hat DIRECTORY SERVER 8.1 - DEPLOYMENT Deployment Manual page 97

• If high availability is the primary concern, create a data center with multiple Directory Servers on a
single site. Single-master replication provides read-failover, while multi-master replication provides
write-failover.
Section 6.3.6, "Using Replication for High Availability"
See
• If local availability is the primary concern, use replication to distribute data geographically to
Directory Servers in local offices around the world. A master copy of all information can be
maintained in a single location, such as the company headquarters, or each local site can manage
the parts of the DIT that are relevant for them.
Section 6.3.7, "Using Replication for Local Availability"
See
• In all cases, balance the load of requests serviced by the Directory Servers and avoid network
congestion.
Section 6.3.8, "Using Replication for Load Balancing"
See
After planning the replication strategy, it is possible to deploy the directory service. It is best to deploy
the directory service in stages, because this allows administrators to adjust the directory service
according to the loads that the enterprise places on the directory service. Unless the load analysis
is based on an already operating directory, be prepared to alter the directory services as the real-life
demands on the directory become clear.
6.3.1. Conducting a Replication Survey
Gather information about the network quality and usage in the site survey to help define the replication
strategy:
• The quality of the LANs and WANs connecting different buildings or remote sites and the amount of
available bandwidth.
• The physical location of users, how many users are at each site, and their usage patterns; i.e., how
they intend to use the directory service.
• The number of applications that access the directory service and the relative percentage of read,
search, and compare operations to write operations.
• If the messaging server uses the directory, find out how many operations it performs for each email
message it handles. Other products that rely on the directory service are typically products such as
authentication applications or meta-directory applications. For each one, determine the type and
frequency of operations that are performed in the directory service.
• The number and size of the entries stored in the directory service.
A site that manages human resource databases or financial information is likely to put a heavier
load on the directory service than a site containing engineering staff that uses the directory solely for
telephone book purposes.
6.3.2. Replicated Selected Attributes with Fractional Replication
Fractional replication allows the administrator to choose a set of attributes that are not transmitted
from a supplier to the consumer (or another supplier). Administrators can therefore replicate a
database without replicating all the information that it contains.
Conducting a Replication Survey
for more information.
for more information.
for more information.
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