REVIEWS

Novell's NDS Enhancement Pack Fixes Some Problems, Ignores Others

by James Drews

If at first you don't succeed, try, try again. Novell's doing just that with its NetWare Directory Services (NDS) Enhancement Pack. While it didn't solve all of our NDS problems at the University of Wisconsin-Madison, it did help.

The NDS Enhancement pack contains three new NetWare Loadable Modules (NLM) for NetWare 4.1 servers: DS.NLM, DSREPAIR.NLM and DSMAINT.NLM. You can install the new NLMs on NetWare 4.1 servers and use them without taking down the system. We installed the DS Enhancement pack on our 10 NetWare 4.1 servers and had it running in about 45 minutes. Older versions of NetWare can't take advantage of the new DS.NLM because it's tightly coupled with the server opera ting system (it's part of SERVER.EXE), but can take advantage of the other two NLMs.

DS.NLM Enhancements The new DS.NLM (the heart of the NDS code) includes several performance improvements. Novell claims to have improved the performance NDS' login and authentication processes, especially when many workstations attempt to login at once. We certainly noticed the improved performance with faster login times. Novell has also improved the background synchronization process of the DS.NLM running on each server. These processes generally go unnoticed by the end user, but should now consume less CPU time.
Novell has also added the "partition status" attribute, which records the last time that NDS synchronization was successfully completed on a partition. This information can be read with the new DSREPAIR included in the enhancement pack. With this attribute, you can quickly see if NDS is having trouble synchronizing the NDS database between servers. We really found this useful, s ince we can check the status in DSREPAIR on just a couple of our servers to see if there are any synchronization problems in the entire tree.

Novell also claims that the new DS.NLM contains more "self healing" properties. We talked to some colleagues at Indiana University, who had several severe NDS problems last summer involving corrupt objects, synchronization failures and persistent server utilization of 100 percent. They also had some partition operations (like "delete replica" or "create new partition") that were never completed. However, since they installed NDS 4.89a and the 410pt1 patch, they haven't seen any such problems.

Objection Sustained One of the Enhancement Pack's best features is the DSMAINT.NLM. Before, if you ever needed to replace the NetWare SYS volume on the server you had to: uninstall NDS, replace the drive and reinstall the NDS. This creates real problems with Bindery-based programs, because the unique Object ID for each o bject changes when you reinstall the NDS since NDS does not have a global unique Object ID for every object. This results in two common problems: You must redo, or at least correct, the mail directory structure (SYS:MAIL), and bindery-based programs that log information based on Object ID will now render the log files unusable.
For instance, most bindery-based programs (like software metering packages) will store information in the log file based on the User Object ID instead of the object name to conserve disk space (four bytes to store an Object ID vs. 48 bytes for the object name). After reinstalling the NDS, the Object ID stored in the file will point to an object that doesn't exist or, even worse, the wrong object. With DSMAINT.NLM, the user Object IDs can be preserved. Novell should have released this NLM from day one.

NDS Distractions Thes e new NLMs are good improvements, but all still isn't perfect in NDS land. At the Computer-Aided Engineering Center, our production NetWare 4.1 servers are experiencing some severe performance problems from NDS synchronization. Our user community is complaining about the length of time it takes to run NetWare-aware applications. That is, programs that access the NDS or Bindery appear to "hang" occasionally or run very poorly when accessing the NDS/Bindery emulated object.

For example, PCONSOLE will quite regularly take up to two minutes to retrieve and display the list of 40 or so print queues. These problems only occur on the servers holding a replica of our Students.Engr context, which contains more than 4,000 objects. Access to the file system (reading and writing files) on these servers remains unaffected.

In our discussions with Novell's tech support, we've come across two problems: NDS does not handle groups with more than 500 members very well, and each NDS context should contain fewer than 1,500 objects. Novell also recommends that each partition be limited to 1,500 objects. We have removed our need for th e large NetWare groups. The update did not correct all of the performance problems we were experiencing, but the changes made in the login and authentication code did help speed up our user's login process.

The second issue is an NDS design problem. The NDS tree can have many thousands of objects, just not all in the same NDS context. Novell recommends that the NDS hierarchy be designed in a triangular shape, rather than the flat model. This is a rather poor limitation. Novell is aware of these issues and will be issuing design guidelines for the NDS tree for universities. These guidelines should be available by the time this article is published.

The NDS Enhancement Pack is available on CompuServe in the NetWire forum and Novell's FTP site (ftp.novell.com). The update is free for all users of NetWare 4.

James E. Drews is a network administrator for the Computer Aided Engineering Center of the University of Wisconsin-Madison. He can be reached at drews@engr.wisc.edu

Improvement In The NDS Enhancement Pack

Novell's recent release of the NDS Enhancement Pack provides the following advances:
Increased performance with user Login and Authentication routines
Improved "resolve name" routines find DS objects quicker
Better handling of down links between servers
Background synchronization and replication improvements
Bindery emulation performance enhancements
Bindery emulation can now handle an object name that exists in more than three emulated contexts
Addition of the "Partition Status" attribute to provide faster and additional NDS management capabilities
Changes to add more self-healing to the NDS
New DSREPAIR that will identify and correct more possible data inconsistencies
DSMAINT.NLM included to assist in hardware maintenance of 4.1 servers

Vendor Information
NDS Enhancement Pack, free of charge, available for download online through the NetWire forum on CompuServe (GONETWIRE) and http://www.novell.com Novell, (800) NETWARE; fax (800) 638-9273. http://www.novell.com

Microsoft Service for NetWare Directory Services, free of charge, available for download online from the Internet (http://www.windows.microsoft.com), MSN and CompuServe, Microsoft Corp., (800) 426-9400, (206) 882-8080; fax (206) 936-7329. http://www.microsoft.com

January 15, 1996