eDirectory Background Processes

This section provides a look at the main background processes that do all the heavy lifting associated with eDirectory operations. They are

• Database initialization

• Flat cleaner

• Janitor

• Replica sync

• Replica purger

• Limber

• Backlinker

• Schema sync

• Time sync

When you use the various eDirectory monitoring and repair tools, of which some were discussed in Chapter 5, "Novell eDirectory Management," and more are discussed later in this appendix, these background processes and their effects are what you monitor and repair. For this reason, it's a good idea to know a little bit about what you are looking at.

Database Initialization

The Database Initialization (DB Init) background process is automatically initiated whenever the file system is mounted on the eDirectory server. It also executes any time the eDirectory database is opened or when eDirectory is reloaded. DB Init is responsible for

• Verifying the usability of the eDirectory database files on this server

• Scheduling the running of other eDirectory background processes

• Initializing the various global variables and data structures used by eDirectory

• Opening the eDirectory database files for use by the version of eDirectory running on this server

DSTrace provides the capability to monitor the DB Init process directly.

Flat Cleaner

The Flat Cleaner background process is used to eliminate eDirectory variables and attributes that are no longer needed by the database. Flat Cleaner is responsible for

• Eliminating unused bindery and external reference (X-ref) objects and/or attributes.

• Making sure that each of the objects in a partition replica maintained on this server has a valid public key attribute.

• Eliminating X-ref obituaries that have been set as purgeable.

• Making sure that the Server objects in partition replicas hosted on this server have maintained accurate Status and Version attributes. The Server object maintains an attribute that specifies server statusup, down, initializing, and so on. It also keeps a record of the version of eDirectory running on that server.

Flat Cleaner can be indirectly monitored through the use of Check External References in DSRepair . DSTrace also provides the capability to monitor the Janitor process directly.

Janitor

As its name implies, the Janitor process is responsible for routine cleanup of eDirectory environment. Janitor is responsible for

• Monitoring the value of the NCP status attribute maintained in the eDirectory Server object for this server.

• Keeping track of the [Root] -most partition replica on the server and the overall replica depth of the server. The [Root] -most partition is the partition root object highest in the tree ( closest to [Root] ). Replica depth describes how many levels down from [Root] the highest partition replica hosted by that server is.

• Executing the Flat Cleaner process at regular intervals.

• Optimizing the eDirectory database at regular intervals.

• Reporting synthetic time use by a partition replica on the server. Synthetic time occurs when a server clock set to a future time is reset to the correct time. Any eDirectory changes made while the clock was set at the future time will bear incorrect timestamps. This problem will self-correct as long as the gap between current and synthetic time is not too large.

• Making sure the inherited rights for each partition root object on this server are properly maintained.

Like Flat Cleaner, Janitor can be monitored indirectly by examining the Replica Ring repair options, Time Synchronization status, and Replica Synchronization status operations with DSRepair . DSTrace also provides the ability to monitor the Janitor process directly.

Replica Sync

The Replica Synchronization background process is responsible for two primary tasks :

• Distributing modifications to eDirectory objects contained within partition replicas maintained by the eDirectory server

• Receiving and processing partition operations involving partition replicas hosted by the eDirectory server

DSRepair can report the status of the replica synchronization process from a number of different perspectives:

• Report synchronization status

• Report synchronization status of all servers

• Report synchronization status on the selected server

DSTrace also provides the ability to monitor the Replica Synchronization process directly.

Replica Purger

Replica Sync schedules the execution of the Replica Purger background process. It is responsible for

• Purging any unused objects and/or attributes that exist in eDirectory partition replicas hosted on this server

• Processing obituaries for objects maintained within partition replicas hosted on this server

DSTrace also provides the ability to monitor the Replica Purger process directly, commonly referred to as Skulker .

Limber

After questioning several sources, it is still unclear why this process is named Limber, so that will remain a mystery for now. However, naming issues aside, Limber is responsible for

• Making sure that the eDirectory referral information for this server is properly maintained in each partition hosted on this server.

• Making sure that the server hosting the Master replica of the partition in which the Server object for this server resides has the correct Relative Distinguished Name (RDN) for this server. The RDN identifies a target eDirectory object's context in relation to the context of the source eDirectory object. For example, the Admin object in O = Quills would receive the following RDN for CN = jharris.OU = Education.OU = Provo.O = Quills : jharris.Education.Provo . The O = Quills is assumed from the location of the Admin object itself.

• Making sure the server object in eDirectory correctly reflects the operating system version and network address in use on this server.

• Making sure the name of the eDirectory tree in which this server resides is correctly reported .

• Monitoring the external reference/DRL links between this server and the partition replica that holds this server's eDirectory Server object. This is done to make sure that the eDirectory server can be properly accessed via its eDirectory object.

• Making sure this server's identification information is correct.

Limber can be monitored indirectly through Check External Reference, Report Synchronization Status, and Replica Ring repair options in DSRepair . DSTrace also provides the ability to monitor Limber directly.

Backlinker

The Backlinker background process helps maintain referential integrity within the eDirectory environment. Backlinker is responsible for

• Making sure that all external references (X-refs) maintained by this server are still required.

• Making sure that each X-ref is properly backlinked to a server that hosts a partition replica that holds the eDirectory object specified in the X-ref.

• Eliminating X-refs that are no longer necessary. As part of doing this, the server hosting the partition replica that holds the referenced eDirectory object is notified of the elimination of the X-ref.

Backlinker can be monitored indirectly through Check External References in DSRepair . DSTrace also provides the ability to monitor Backlinker directly.

Schema Sync

The Schema Sync background process is responsible for synchronizing the schema updates received by this server with other eDirectory servers. DSTrace also provides the ability to monitor Schema Synchronization directly.

Time Sync

Although time sync is not an eDirectory process, it is necessary in order to perform some partition operations such as moves and merges. The underlying time sync mechanism is not important as long as the eDirectory servers are, in fact, synchronized. Time sync can be monitored directly through the Time Synchronization option in DSRepair .

DSTrace with iMonitor

Now that you have been introduced to the most common eDirectory processes, it's important that you know how to keep track of the health and general operation of those processes. To do this you can use iMonitor. iMonitor is presented in Chapter 3, "Novell Management Tools," as one of the principal management tools for NetWare 6.5. However, this section focuses on the iMonitor options for monitoring eDirectory processes and activities. Refer to Chapter 3 for information on iMonitor installation, general interface, and additional capabilities. For detailed feature information, see the NetWare 6.5 online documentation.

iMonitor is a Web-based replacement for several of the console-based management utilities used with previous versions of NetWare, including DSBrowse , DSTrace , and DSDiag . Because the eDirectory processes discussed previously run on each eDirectory server, iMonitor provides a server-level view of eDirectory health as opposed to a tree-level view. You can view the health of processes running only on the server from which you are running iMonitor. To view another server, launch iMonitor from that server.

Prior to using DSTrace from iMonitor, you must configure the utility and specify the activity that you want to monitor. This is accomplished from the Trace Configuration page, shown in Figure D.1.

Figure D.1. Trace Configuration page in iMonitor.

When you go into Trace Configuration, you will see four new links in the left navigation frame:

• Trace Configuration: This is the default view you will see when entering the Trace Configuration page. From this page, you can define the server-based eDirectory events and processes that you want to trace. The following configuration options are available from this page:

  • Trace On/Off: Enables/disables DSTrace monitoring. When DSTrace is enabled, you will see a Trace button (big lightning bolt) in iMonitor's header frame that you can use to view the active trace (see Figure D.2).

    Figure D.2. Active DSTrace view in iMonitor.

    

    NOTE

    DSTrace can increase CPU utilization significantly and reduce performance, so you should trace only when you are actively looking for something, and not as a standard practice.

    
    

  • Update: Applies new configuration options to an existing trace.

  • Trace Line Prefixes: These options let you specify what type of descriptive information to include with each trace line. These prefixes allow you to identify event sequence, group related messages together, and determine how long ago a problem occurred. This can be critical when analyzing DSTrace data, particularly historical trace data.

  • DSTrace Options: Specifies the eDirectory activities that you want to trace for this particular eDirectory server. In order to control the amount of data that you will have to sift through in DSTrace , it's best to restrict tracing to only those specific events that are of interest instead of tracing everything. Table D.1 provides a brief description of many of the common trace options.

• Event Configuration: This link provides a view similar to Trace Configuration, but it lets you select eDirectory events that you want to trace. eDirectory events include such things as adding/deleting objects, modifying attributes, and changing a password. The same configuration options described for Trace Configuration are available for Event Configuration, except that instead of listing DSTrace options, DS Events are listed.

• Trace History: From this page you can view a list of previous traces. A timestamp indicating the period of time during which the trace was gathered identifies each trace.

• Trace Triggers: This page lists some common DS Agent activities and identifies the DSTrace options that must be selected in order to trace that type of DS Agent activity. Selecting trigger options and clicking Submit will add those DSTrace options to the list of active DSTrace options, if they are not already active.

Table D.1. Common DSTrace Options

OPTION NAME	DESCRIPTION
Allocated Memory	Trace messages related to allocation of memory for eDirectory processes.
Audit	Trace messages related to the eDirectory audit process.
Audit NCP	Trace Audit NCP (NetWare Core Protocol) events.
Audit Skulk	Trace audit messages related to the replica sync process.
Authentication	Trace messages related to eDirectory authentication events.
Backlinker	Trace messages related to the Backlink process.
Buffers	Trace messages related to allocation of inbound and outbound packet buffers related to eDirectory requests .
Change Cache	Trace messages related to the changing of the eDirectory memory cache.
Client Buffers	Events related to memory buffers maintained for client connections.
Collisions	Trace messages related to the receipt of duplicate update packets. These duplicate packets usually occur on very busy networks.
Distributed References	Trace messages related to Distributed Reference Link operations.
DNS	Trace messages related to Domain Name Service requests.
DS Agent	Trace messages related to general eDirectory agent activities on this server.
Emulated Bindery	Trace messages related to Bindery Emulation.
Fragmented Requests	Trace messages related to the packet fragmenter that breaks up eDirectory messages for transmission in multiple packets.
Inbound Synchronization	Trace messages related to incoming eDirectory synchronization requests.
Initialization	Trace messages related to the opening of the local eDirectory database.
Inspector	Messages related to the Inspector process. Inspector is part of the Janitor that verifies the structural integrity of the eDirectory database.
Janitor	Trace Janitor messages. The Janitor cleans up eDirectory by removing objects that are no longer needed.
LDAP	Trace messages related to LDAP communications.
LDAP Stack	Trace messages related to the memory stack associated with LDAP operations.
Limber	Trace Limber messages. The Limber monitors connectivity between all replicas.
Locking	Trace messages related to manipulation of the local eDirectory database locks.
Lost Entry	Trace messages related to obituaries, eDirectory attributes, and stream files.
Move Object	Trace messages related to eDirectory object move operations.
NCP Engine	Trace messages related to the NCP engine.
Outbound Synchronization	Trace messages related to background replica synchronization.
Partition	Trace partition operations and messages.
Purge	Trace replica purger messages.
Resolve Name	Trace messages related to eDirectory name resolution when traversing the eDirectory tree.
SAP	Trace messages related to the SAP protocol.
Schema	Trace schema modification and synchronization messages.
Server Packets	Trace messages related to server packets.
Streams	Trace messages related to stream attributes in eDirectory.
Thread Scheduling	Trace messages related to the management of processor threads used with eDirectory.
Time Vectors	Trace messages related to transitive vectors, which describe how caught up the replica is in the synchronization process.
Wanman	Trace messages related to WAN Traffic Manager.