Novell Network Management: NetWare 6

Chapter 8: Use iMonitor to Manage and Maintain eDirectory

 

Objectives:

This chapter concerns replication and synchronizing replicas, eDirectory administration, and network time synchronization. The objectives important to this chapter are found on page 8-1:

  1. Identify What iMonitor is and How to Use It
  2. Use iMonitor to Diagnose and Repair eDirectory Problems
  3. Repair eDirectory Using iMonitor
  4. Maintain and Optimize eDirectory Using Cache Options
Concepts:

Identify What iMonitor is and How to Use It

For those with NetWare console experience, iMonitor can be thought of as an IP based MONITOR utility. You can run it from any workstation on your IP network, and may be able to run it from any computer with access to the Internet.

iMonitor runs in a browser, but there are still specific requirements to use it:

  • Browser - must be Internet Explorer 4 (or later), Netscape browser 4.06 (or later), or the NetWare browser.
  • Platform - can be run on several network platforms: NetWare 5 with Support Pack 5 (or later), Windows NT or 2000, Linux, Solaris, Tru64 Unix.
  • eDirectory - must be used with eDirectory 8.5 (or later). If your network includes servers running the platforms listed above, iMonitor will access whatever other versions of eDirectory are running on them as well. Be aware that NetWare 6 comes with eDirectory 8.6.
  1. To run iMonitor, first make sure that the correct NLM is running on your eDirectory server: NDSIMON.NLM. You can make sure that it runs when the server boots by putting the command to load it in the server's AUTOEXEC.NCF file.
  2. Begin to run the utility by running a browser on a workstation. On the browser's address line, enter:
    http://serverIPaddress:8008/nds-summary
    (This is similar to the command to start Remote Manager.)
  3. Like many web pages, the page that comes up is divided into three sections, called frames. The basic layout is like this:

    Navigation frame - contains buttons to switch between Remote Manager, iManager, and other features
    Assistant frame - contains links to switch between information screens of the feature currently selected








    Main content frame - contains the data that your choices in the other two frames select







Navigation frame - The buttons that appear on the left side of this frame remain fairly constant. The right side changes depending on the iManager feature currently selected. You can expect to find buttons for Help, Login/logout, Remote Manager, DSTRACE, and eDirectory Repair.

Assistant frame - Links appear here that change the content of the Main frame. Click links to features related to Directory Service Agents, which the text defines as instances of eDirectory running on specific servers. Think of a DS Agent as a server running eDirectory. To run eDirectory, the server must run the DS.NLM program.

Main content frame - As noted above, this frame presents the information requested with the controls in the other frames. It also presents links to drill down to more specific information, and interfaces to change the values of settings.

iMonitor can be configured with settings in SYS:\SYSTEM\NDSIMON.INI. This plain text file has a series of settings in it, which are all remarked by default. Removing the remark marker at the beginning of a line would enable the setting on that line. (As with other NetWare configuration files, any line that begins with # as the first character is considered remarked, and is ignored by the operating system.)

Use iMonitor to Diagnose and Repair eDirectory Problems

iMonitor has several features for monitoring eDirectory. They can be broken into four categories. Of course, it wouldn't be a Novell book unless they broke the topics into subtopics:

  • Health Check- You can check the "health" or status of Agents, individual partitions, and partition rings. The color scheme of traffic lights continues here: green is good, yellow is for problems, and red is for serious problems. Subtopics about health:
    • Agent Health
      • One Successful Time Synch tells you if the server has been able to synchronize its time with eDirectory time.
      • Time Delta Tolerance shows the difference (in seconds) between the time on the agent and time on your device running iMonitor. It may help to remember that Delta is a standard engineering symbol for change or difference.
      • DS Loaded - Is the Directory loaded?
      • DS Open - Which of six states is the Directory in? The only functional state is Open.
    • Partition Health - This server may hold replicas of several partitions. This screen will show the health of each of them, and provide the link to the ring/list for each partition you have a replica of. You will get warnings if replica synchronization is taking longer than four hours, or if a partition has less than three replicas.
    • Ring Health - Among other data, you can verify that the recommended minimum three replicas exist for a partition, and read the number of subordinate references that exist for a partition.

      The text pauses here to discuss another concept of replica status: status with regard to being created, removed, joined, split, moved, changed to another replica type, or left alone. The text calls this transitional status.
  • Agent Configuration - Remember that a DS Agent is the instance of eDirectory running on a particular server. You can configure eDirectory on a server with this tool. For example, you can verify the version of eDirectory the server is running, which really means you can verify the version of DS.NLM the server is running. You can also run background processes with the Agent Triggers link in the Assistant frame.
  • Agent Synchronization - Provides information such as number of replicas with errors, time since last synchronization, maximum time to achieve synchronization (called Maximum Ring Delta), and Replica's Perishable Data Delta, which means the amount of data, still unsynchronized, that would be lost if this replica is lost.
  • Trace Configuration - The Trace utility allows you to watch synchronization traffic. Trace increases the load on the processor where it is running, and increases network traffic, so do not run it all the time.
Repair eDirectory Using iMonitor

iMonitor has a Repair option in its Navigation frame, which enables an administrator to perform eDirectory repairs. In order to repair a partition replica, first select it, then select Repair. To repair a single eDirectory object, select that object, then click Repair. A helpful choice from previous versions is Run in Unattended Mode, which tells the utility to run without interaction from the operator, correcting what it can.

The text refers to the eDirectory database as a DIB set. This refers to the set of files that eDirectory is stored in.

  • NDS.DB - This is a rollback file, used to back out of transactions that have completed
  • NDS*.LOG - This is a roll forward file, used to complete transactions that have not been completed
  • NDS.01 - This is an actual database file, which can hold up to 2 GB of information. When your eDirectory information grows larger than 2 GB, NDS.02 is created. More files are created as the eDirectory grows.
  • hex.NDS - The first few characters of this series of files are hexadecimal numbers. They are streams files, and they hold login scripts and print job configurations.

DIB set files can be archived on the server. When an archive is no longer needed, the archive can be deleted with the Delete Old DIB Set option. The text makes a special note that once performed, you cannot undo this deletion.

The discussion of advanced options uses a term that is not defined until the next chapter: Obituary. Think of an Obituary as a placeholder for an object that has been moved or deleted from its place in the tree. The Obituary exists as update information for the other replicas of this partition that have not been synchronized yet.

A feature that is offered, but not recommended, by Novell is Schedule Report. A better name would have been Schedule Repair, since that is what it really does. Novell suggests running repairs as needed, not at set intervals. This may be partly because the repair utility only repairs the replicas on the server where it runs, and this may cause problems until you run it on other servers holding replicas of the same partition.

Maintain and Optimize eDirectory Using Cache Options

Previous versions of eDirectory used block cache, which are copies of physical blocks from the hard drive, stored in server RAM for quicker access. eDirectory 8.6 uses block cache and entry cache. Entry cache is a representation of the eDirectory structure, stored in server RAM, that enables the server to locate data in the block cache faster.

Some data is offered about the services that each kind of cache will enhance:
Service Improved by Block Cache? Improved by Entry Cache?
Update operations
yes
 
Browse operations  
yes
Queries
yes
yes
Index searches
yes
 
Retrieval of entries  
yes

 

If you allocated a specific amount of memory as block cache in an earlier version of eDirectory (default was 8 MB), then you should double the amount to allocate as cache memory in eDirectory 8.6. This amount of memory will be shared between block cache and entry cache.

Previous versions of eDirectory stored information in block cache, but did not efficiently clean out old data when done using it. eDirectory 8.6 browses the blocks and cleans them. By default, this is done every 15 seconds.

Novell recommends that you try for a 1:1 ratio between block cache size and eDirectory database size. This will give faster access to data. Two different ratios are recommended for entry cache size: either 1:2 or 1:4. Other ratios between entry cache and database sizes are not recommended.

It is possible to allocate cache memory by one of two methods. Note that you must choose one, since the methods are mutually exclusive. The methods are Dynamically Adjusting Limit and Fixed Memory Limit. Whichever you use at any given time becomes the new default for that server.

The description in the text of default memory cache allocation is hard to understand. What it means is this:

  • If a server does not hold a replica, it will use Fixed Memory Limit by default. The cache size will be 16 MB, which will be split evenly: 8 MB for block cache, and 8 MB for entry cache.
  • If a server does hold a replica, it will use Dynamically Adjusting Limit by default. This will be 51% of available server memory, with the following exceptions. It will use no less than 8 MB per cache, and it will grow, but will reserve 24 MB of memory for use by other processes. For example, if the server had 256 MB of RAM available, the block cache would start at 8 MB, and the entry cache would start at 8 MB. The two caches together would grow no larger than 232 MB (256 minus 24). This is actually more complicated, as explained below.

Dynamically Adjusting Limit - As the name states, this is a dynamic process, so the amount of memory available to cache can vary with the amount of memory available from the server at any given moment. The administrator sets the percentage of available memory to use for cache.

As implied above, you also set the minimum and maximum cache size. The default minimum is 16 MB. The default maximum value is 4 GB. It is possible to set these values in conflict. In case of a conflict, the server uses the value for minimum. The time between dynamic recalculation and adjustment can be set by the administrator. By default, this interval is 15 seconds.

Fixed Memory Limit - This method was used in earlier versions of eDirectory, and it continues to be an option. In fact you can set this to work three ways:

  • Fixed - Assign a specific amount of bytes to be used for cache memory.
  • Percentage of Physical - This is a percentage of the total amount of memory in the server.
  • Percentage of Available Physical - This is a percentage of the memory actually available to the process as the server boots up. Note that it does not adjust dynamically later.

Changes to cache can be made through iMonitor. The text recommends running ConsoleOne, right-clicking a server object, and choosing Launch iMonitor. Sign in as an administrator, choose Agent Configuration on the Navigation frame, and find Settings. Under the Database Cache link, you will be able to change all the settings described above.