8.17. Monitoring Replication Status

The replication status can be viewed in the Directory Server Console or Red Hat Administration Express.

8.17.1. Monitoring Replication Status from the Directory Server Console

To view a summary of replication status in the Directory Server Console. do the following:

Open the Directory Server Console.
Select the Status tab, and then, in the left navigation tree, select Replication Status.
In the right pane, a table appears that contains information about each of the replication agreements configured for this server.
Click Refresh to update the contents of the tab.
The status information displayed is described in Table 8.6, “Directory Server Console Replication Status”.

Table Header	Description
Agreement	The name of the replication agreement.
Replica suffix	The suffix that is replicated.
Supplier	The supplier server in the agreement.
Consumer	The consumer server in the agreement.
Number of changes	The number of changes sent to this replica since the server started.
Last replica update began	The time when the most recent replication update started.
Last replica update ended	The time when the most recent replication update ended.
Last update message	The status for the most recent replication updates.
Consumer initialization	The current status on consumer initialization (in progress or not).
Last consumer initialization update message	The status on the last initialization of the consumer.
Last consumer initialization began	The time when the initialization of the consumer replica started.
Last consumer initialization ended	The time when the initialization of the consumer replica ended.

Table 8.6. Directory Server Console Replication Status

8.17.2. Monitoring Replication Status from Administration Express

Although the replication status report in the Directory Server Console shows many details, it does not show the progress of the replication. Additionally, because one report is generated per agreement, this lists all status reports for all different agreements.

The repl-monitor.pl script, which is explained in detail in the Directory Server Configuration, Command, and File Reference, monitors replication status to a greater extent by providing these functionalities:

Lists for each supplier replica on each Directory Server discovered, server URL or alias, replica ID, replica root, and maximum change sequence number (maxcsn).
Lists corresponding to each supplier replica listed above and for each direct or indirect consumer replicas discovered, server URL or alias, replica root, replica type, connection type of the replication sessions, replication schedule, replication status, supplier maxcsn, and time lag between the consumer maxcsn and the supplier maxcsn.
The time lag field uses different colors to indicate the degree of time lag. The threshold for each color is configurable.
Displays the change sequence number (CSN) in human-readable format (instead of hex strings) in the MM/DD/YYYY HH:MI Seq# SubSeq# format, where Seq# and SubSeq# are omitted if they are zero.
Shows the output/result in the HTML format. The script writes the output to an HTML file, which can be configured to refresh itself automatically; the refresh interval is also configurable.

The script is integrated into the Red Hat Administration Express, so the replication status can be viewed in a web browser. The Administration Express is an HTML-based version of Red Hat Console that provides quick access to servers running Administration Server.

To view in-progress status of replication in Administration Express, do the following:

Prepare a configuration file following the guidelines provided in the "repl-monitor.pl (Monitor replication status)" section of the Directory Server Configuration, Command, and File Reference.

Open the Administration Server URL in a web browser.

http://hostname:admin_port

Click Red Hat Administration Express, and, when prompted, log in.

Select a supplier Directory Server instance, and click Replication Status.

This brings up a page for specifying the runtime parameters of the replication-monitoring tool.

In the Configuration file field, type the path to the configuration file created in step 1, and click OK.

The replication-status page appears; by default, the page gets refreshed every 300 seconds.

Each table shows the status of the changes originated from a supplier replica.

Table	Description
Table Header	The table header shows the replica ID of the supplier replica, the replica root, and the maximum Change State Number (CSN) on the supplier. The important thing is to make sure that each supplier LDAP server has its unique replica ID. Multiple replica roots on one LDAP server, however, could share the same replica ID.
Table Row	Each row represents a direct or indirect consumer of the supplier (identified in the Table Header).
Max CSN	It is the most recent CSN the consumer has replayed that was originated from the supplier (identified in the Table Header).
Time Lag	It shows the time difference between the supplier and the consumer's max CSNs for the changes originated from the supplier (identified in the Table Header). A consumer is in sync with its supplier when its time lag is `0`.
Last Modify Time	It is roughly the time when the consumer's max CSN was replayed.
Supplier	This column lists all the suppliers of the consumer.
Sent/Skipped	Each supplier lists roughly how many changes originated from the supplier (identified in the Table Header) have been replayed or skipped by the consumer. The numbers are kept in suppliers' memory only. They will be cleared if the supplier is restarted.
Update Status	The number is the status code, and the string is the implication of the status code. Watch this column for possible deadlock if all the suppliers complain that they cannot acquire the busy replica. It is normal if one of the suppliers is doing an update while the others can't acquire the busy replica.