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Understanding and Deploying LDAP Directory Services > 15. Going Production > Advice for Going Production

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Advice for Going Production

There are a few more things you should consider before you begin to execute your production plan. In this section we present some advice that will help you avoid mistakes others have made and achieve a smooth rollout of your production directory service.

Don't Jump the Gun

The most important advice we can give is Don't go production until you are ready . The biggest mistake people often make is to skip one or more essential design steps. This usually leads to a deficient , hard-to-maintain service. You might find that you need to go back and perform the steps you left out and then redeploy your entire service. In the long run, the time you save up front by skipping some of the directory design work will be greatly outweighed by the aggravation you cause yourself and the users of your service.

The other major preproduction task that many are tempted to omit is the directory service pilot (described in Chapter 13, "Piloting Your Directory Service" ). A pilot service is the best way to prove your directory design and learn what it's like to run a production service. By creating a pilot service and heeding the lessons learned, you will greatly increase the chances of success for your production service.

Don't Lose Focus

Another common mistake is to lose focus and forget what you are trying to accomplish. Always keep your production success criteria in mind as you proceed with your deployment. Remind yourself who your most important users are and think about what you need to do to meet their needs. Work diligently to ensure that your most important directory-enabled applications succeed. The success of your service is linked closely to the success of those applications.

Adopt an Incremental Approach

One of the running themes throughout this book is that an incremental approach is more likely to succeed than an all-or-nothing approach. This is especially true when rolling out a production directory service. Don't try to add too many dependent applications the first day your service is up and running. Don't create unrealistic expectations by overhyping your service. Don't try to roll out all the replicas your design includes in the first few days of service; adopt a phased approach and ensure that each new part of the service is working before increasing the complexity of the system.

Prepare Yourself Well

There is an old story about a passenger train engineer who was faced with a crisis. While traveling with a full complement of passengers at high speed, his train came upon a single empty freight car that someone had mistakenly left on the main track instead of on a nearby siding. The situation is depicted in Figure 15.1.

Figure 15.1 A dangerous situation.

Without missing a beat, the engineer immediately increased his engine speed to full throttle . His passenger train struck the empty freight car at nearly full speed, knocking it off the track and out of the way and avoiding derailing his own train.

After the incident, when the engineer was asked how he knew to increase his speed, rather than try to stop, he had a ready answer: "I knew how far I was from the empty car because many times in the past, as I passed by that same stretch of track, I imagined that same exact situation and thought about what I would do. I knew that if I was too close to stop in time, I should increase my speed because the impulse created by striking the empty car would most likely drive it off the track and safely out of the path of my own train. I didn't have to think about any of this at the time of the crisis because I already knew exactly what to do."

The moral of the story is, of course, be prepared for whatever might come your way. This is good advice, and you should apply it to your production directory service. You should think ahead and prepare yourself as much as possible for your production rollout. Consider what is likely to go right and how things might go wrong. Play "what if" games and consider how you will adapt to any situation that arises, and change your strategy if necessary. Like the train engineer, you will be able to act very quickly and decisively if you prepare yourself.

Potential problem areas to consider include the following:

  • Bugs in hardware or software.   If these crop up, you may need to adjust your design to work around the problem, or you may just need to wait for a bug fix from a vendor.

  • Flaws in your design, software, or hardware that lead to inadequate capacity for your service.   If you can afford it, pad your estimates so you have extra capacity. If necessary, be prepared to slow down your rollout to reduce the load on the system until you can install additional servers.

  • Unexpected hardware failures.   This will lead to inadequate capacity or complete disruption of your service. If you can arrange it, have extra hardware lined up that you can borrow in case an unexpected failure occurs.

  • Changes in the requirements for your service.   Any major change in requirements will require you to take a step back and consider how you need to adjust your rollout plans. For example, if you find out that your service must support a new directory-enabled application, you may need to reconfigure servers to add new schemas, configure additional indexes, or make other changes to accommodate it.

  • Staffing shortages.   These might occur because of illness , family emergency, or people being called away to address problems in other production systems they are also responsible for. You can reduce the pain caused by a staffing shortage by ensuring that each person involved in your directory service rollout has trained another person who can handle his or her tasks in an emergency.

Be realistic about the risks involved in your production plan, and think about how you will detect problems and what you will do if they occur. Make sure you inform your management and the owners of directory-dependent applications and services of the risks so they are not surprised by the problems or your actions.

As an example of the kind of thinking you should do, suppose your design calls for you to roll out five replica servers to provide service to a busy directory-enabled mail delivery service. Consider what you would do during your production rollout if you found a critical bug in your directory service software that prevents you from creating more than three replicas. Clearly this would reduce the capacity of your service. You must decide whether three replicas would be able to handle the application load long enough to get a patch from your directory server software vendor, or if instead you would need to scale back the mail service ”or possibly delay your directory service rollout entirely. Depending on the situation, any of these options might be the best choice. By thinking about the options in advance, you will be able to act quickly and decisively if problems occur during your rollout.



Understanding and Deploying LDAP Directory Services,  2002 New Riders Publishing
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Index terms contained in this section

directories
         production
                    incremental approaches
                    losing focus
                    preparing for anything 2nd 3rd 4th 5th
                    taking your time 2nd 3rd
planning
         production rollouts
                    incremental approaches
                    losing focus
                    preparing for anything 2nd 3rd 4th 5th
                    taking your time 2nd 3rd
production directories
         planning
                    incremental approaches
                    losing focus
                    preparing for anything 2nd 3rd 4th 5th
                    taking your time 2nd 3rd

2002, O'Reilly & Associates, Inc.



Understanding and Deploying LDAP Directory Services
Understanding and Deploying LDAP Directory Services (2nd Edition)
ISBN: 0672323168
EAN: 2147483647
Year: 1997
Pages: 245

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