Design, Piloting, and Deployment Costs

   

The first half of your directory's life cycle includes all the activity up to the point at which you throw the switch and put your directory into production. The costs associated with this phase can be broken down into three major areas: design costs, piloting costs, and deployment costs.

Design Costs

As discussed in Part II, Designing Your Directory Service, the design phase of your directory's life cycle is the time when you make many important decisions concerning the scope and structure of your directory service. Costs associated with this phase involve primarily staff but include all of the following:

  • Salary and benefits costs . Costs in this category include salary and benefits for you and the staff helping you during the design phase. If your design phase involves people from other groups, such as your Human Resources department, be sure to include salary and benefits costs for them. To quantify these costs, you will invariably have to apportion staff time among the various phases of the directory life cycle. Also be sure to budget time for the deployers to become familiar with the software so that they fully understand its capabilities and limitations.

  • Fees paid to outside contractors . If you retain the services of consultants to assist you in the design phase of your directory project, include the fees paid to them in your total design phase costs. As with salaries and benefits, if you employ the services of consultants beyond the design phase, you may need to assign portions of the costs to each phase of the project.

  • Research material costs . As you design your directory service, you will probably purchase journal subscriptions, special technology reports , and books like this one to assist you in making good design choices.

  • Software costs . During the design phase you may need to purchase copies of the software you plan to deploy. In some instances, you may be able to avoid these costs by using evaluation copies of the software.

  • Training and conference costs . You will need to develop in-house directory expertise; therefore, you may incur costs when you send staff members to training seminars and technology conferences.

Reducing Design Costs

In general, be careful about cutting costs in the design phase of your directory's life cycle. Studies have repeatedly shown that mistakes made during the early part of a project are significantly more expensive to correct than mistakes made later in the project. If in doubt, look for other expenses to reduce.

Consider the relative efficiency of attempting your directory design process solely using in-house expertise versus involving outside consultants. Evaluate the directory-specific knowledge of your staff who will design the directory. Are they familiar with directory technology, or will significant training costs be incurred before design can begin? If directory technology is not something your staff is familiar with, it may be better to bring in consultants who can help you with the design process.

Piloting Costs

During the piloting phase of your directory's life cycle, you obtain valuable information about your directory design. You learn whether your design assumptions are valid, and if they're not, you have the opportunity to revisit your design and make improvements. As in the design phase, reducing costs in the piloting phase is risky; if you don't obtain useful feedback, your design may not be optimal. When you're reducing costs in this phase, be sure that you do not compromise your ability to obtain and respond to feedback from your pilot users.

The following are common costs associated with piloting:

  • Equipment and software costs . Your pilot phase, if done properly, includes an actual small-scale directory deployment. The equipment used to provide this pilot deployment might include CPUs, disks, networking hardware, and software.

  • Staff costs for deployment . During your pilot phase, you will incur costs associated with installing, configuring, and maintaining the pilot hardware and software.

  • Staff costs for publicity, feedback, and analysis . During and after the pilot phase, you will incur costs associated with publicizing your pilot, gathering feedback from pilot users, analyzing that feedback, and refining the directory design and deployment plans.

  • Documentation and training costs . Both vendor and in-house documentation should be available to your users during the pilot phase. You may also find it helpful to your pilot's success to provide training sessions for your users.

  • Incentives for pilot users . To obtain the best possible feedback from your directory pilot, you might choose to provide incentives to reward pilot users for their participation and feedback.

Reducing Piloting Costs

The piloting phase of your directory life cycle is your opportunity to validate your directory design and anticipate potential problems. If your pilot program doesn't give you the information required for a successful deployment, you need to either do another pilot or proceed without it. Neither outcome is desirable, of course.

To reduce piloting costs, pick your pilot participants carefully , explain what you expect from them, and tell them how they will benefit from their participation. If your pilot participants generate useful feedback that helps you validate your basic assumptions and improves the service before it goes into production, your piloting costs represent money well spent.

You can also reduce piloting costs by reusing the pilot hardware when you bring your production directory service online. If your production service will be rolled out in an incremental fashion, you can bring up the initial production service, then dismantle the pilot system and redeploy it into the production environment.

Deployment Hardware Costs

During the deployment phase of your directory service, you will purchase the equipment required to provide the full directory service you've been planning. Deployment hardware costs include the following:

  • Server costs . This category includes the price of server hardware used to run the directory. Be sure to include the costs of standby units you may purchase as hot or cold spares .

  • Memory upgrades . If you purchase your memory preinstalled from the same vendor who supplies your servers, memory costs will already be reflected in the price of your servers. Otherwise, include memory costs in your total deployment costs. Be aware that some server hardware vendors (in particular, those who sell high-end systems) will not honor the factory warranty if third-party options such as memory, disk drives , or network adapters have been installed.

  • Network hardware . Included in this category are network adapter cards, cabling, hubs, routers, terminal servers for remote maintenance, and other equipment. Some of this equipment may already be deployed in support of other services. You may want to apportion costs among the various services connected to the directory. For more information, see the sidebar Apportioning Hardware and Software Costs later in this chapter.

  • Hardware used for monitoring functions . A network management system (NMS) may already exist within your organization, in which case you may need to allocate a portion of your budget to maintenance and upgrades of the existing NMS hardware. If no NMS exists and you plan to monitor your directory service, you may need to purchase a system for NMS functions.

  • High-availability solutions . If your directory must be highly available, you may need to purchase a hardware solution that provides automatic failover across a set of replicated directory servers. Some directory solutions support failover via proprietary technology. However, no current LDAP standard defines how failover is provided. Be aware that high-availability solutions are often provided as part of a storage solution, discussed next .

  • Mass-storage devices . Storage devices for your directory data might include disk drives, redundant array of inexpensive disks (RAID) storage units, or more advanced options, including network-attached storage (NAS) and storage area network (SAN) solutions. High-end NAS and SAN systems are often shared among several services.

  • Backup solutions . Directory data must be backed up to protect against disk failures and disasters such as fires and floods. Backup solutions might include digital linear tape (DLT) or linear tape- open (LTO) units and management software. You may also choose to back up to a mirrored disk drive or use replication to keep a backup server up-to-date with your directory data. If you use a high-end NAS or SAN solution, it will frequently provide an integrated backup management solution, either as a standard feature or as an added-cost option.

  • Physical plant . You need a place to locate the equipment that provides your directory service. You will almost certainly locate it with other computing infrastructure services; therefore, you may need to allocate a portion of your budget to the rental costs and upkeep of this facility.

Reducing Deployment Hardware Costs

There are several ways to reduce the cost of hardware used to provide your directory service. First deploy your directory service on reliable hardware that scales well. This means using server and network hardware that has sufficient capacity for your present needs, as well as enough extra capacity to accommodate six months to a year of anticipated growth. Also be sure that the hardware can be upgraded after that time. When evaluating hardware vendors, consider the following questions:

  • What is the maximum RAM capacity of the server? Is it sufficient for your current and future needs?

  • Does the hardware permit the required level of reliability and redundancy? For example, are any necessary hot-swappable disks and power supplies available?

  • What mass storage options are available? Are they sufficient for the size of directory you plan to deploy? If you use NAS or SAN solutions, can you share the costs of these among several projects?

  • Do the hardware and operating system (OS) support multiple CPUs? Can additional CPUs be added easily? Does the directory server software take advantage of multiple CPUs?

  • Does the operating system for this hardware limit you in an undesirable way? For example, can the operating system support large files (greater than 2GB)? Can it address a large amount of RAM? Can it handle enough network connections to carry the load?

  • Are the costs of maintaining the operating system reasonable? Do you have sufficient in-house expertise on the OS platform, and can it be managed efficiently ?

  • Does the network adapter have sufficient throughput to handle the I/O loads planned? Does the network have sufficient capacity to handle the traffic generated by directory clients and servers?

Purchasing a server without sufficient scaling capacity means that you'll need to replace that hardware at some point in the future. This may be unavoidable considering how quickly CPU speeds are improving and prices are dropping. Ideally you should choose to replace hardware when newer , cheaper, and faster hardware is available, not because your current hardware is overburdened and cannot be upgraded.

Another way to reduce hardware costs is to choose directory server software that runs on multiple hardware and OS platforms. Choosing this type of software allows you the flexibility to select the best hardware for the task instead of limiting you to a single hardware and OS platform. This approach also makes it more likely that you'll be able to choose a hardware vendor with which you already have a relationship, in which case you may be able to leverage existing software and hardware maintenance contracts, and possibly improve your quantity discounts .

Being creative when negotiating pricing can also help you reduce hardware costs. For example, you may purchase hardware in larger quantities . This approach, of course, may be at odds with deploying your directory in a stepwise fashion, in which you might plan to add additional capacity only as the need arises. However, if you have some idea of how your directory needs will expand, you may be able to negotiate a better price from a vendor by committing to purchase the additional hardware over a specified period. If you can pool your purchases with other projects, you may be able to obtain even more favorable pricing.

Finally, to reduce hardware purchase costs, choose directory server software that is efficient and scales well in terms of the following:

  • The total number of directory entries stored

  • The total size of the database

  • The average and maximum sizes of a directory entry

  • The maximum number of concurrent client connections supported

  • The maximum number of LDAP operations that can be performed in a given time period

Although all of the major directory software vendors provide at least reasonable scaling performance for all of these factors, some are better than others in each area. Depending on your directory needs, some performance factors may be more important than others.

Ask the software vendor to suggest reasonable hardware configurations for the directory you plan to deploy. Be sure to provide information both on the number of entries you plan to store in your directory and the type of directory client load you plan to place on the directory. You may find that the minimum hardware requirements vary widely depending on the software vendor. Obviously a directory that can be deployed efficiently on a single server is less expensive to deploy than a directory that requires data to be partitioned among many servers. Does the server software take advantage of multiple CPUs? Alternatively, can additional replicas be deployed easily to handle additional client load?

The answers to all these questions will help you understand how hardware costs will be affected by your choice of directory server software. These answers will also affect your hardware choices. For example, if a directory server does not make effective use of more than four CPUs, there is little benefit in purchasing systems with eight CPUs.

You may be able to reduce your costs further by sharing some of the more expensive components with other projects. For example, most SAN and NAS solutions are designed to be shared among many servers. Similarly, load balancers can usually be logically partitioned to balance load to more than one logical set of servers.

Finally, effort spent tuning your directory service can reduce your costs significantly. A well-tuned server makes more efficient use of the hardware it runs on. For example, Netscape Directory Server 6 operates best when it has cache settings tuned for maximum performance, and when the proper indexes are configured.

Deployment Software Costs

To deploy your directory service, you need several different types of software. You may also need to develop custom software for your directory service. Software costs might include the following:

  • Operating system software . Your servers will require an operating system. Depending on the hardware platform, your OS costs may be one-time costs (possibly with upgrade costs in the future), or they may involve an up-front cost and an annual license or maintenance fee.

  • Operating system enhancements . To enhance performance and reliability, it may be beneficial to purchase additional software that enhances the OS. For example, you may purchase high-performance file system software, disk mirroring software, high-availability software, and clustering software.

  • Directory server software . Directory server software may be priced per server, per seat (per user ), or by another method. Understand the long- term costs of your vendor's pricing model.

  • Utility software . You may find it beneficial to purchase utility software to assist you in data maintenance tasks .

  • NMS software . As described in Chapter 19, Monitoring, you can use a commercially available NMS package such as Aprisma Spectrum Enterprise Manager or HP OpenView, or you can develop custom monitoring software. You may be able to leverage an existing deployed NMS, in which case your costs will be lower.

  • Synchronization software . If you need to synchronize dissimilar directories, you may want to purchase a metadirectory package or develop custom synchronization scripts in-house. If the number of directories that need to be synchronized is small and the synchronization process is straightforward, custom code can be a cost-effective solution. When there are many directories to be synchronized, or the data flow is complicated, a metadirectory may be required.

  • Directory client software for end users . This category may include commercially available client software or custom-developed software such as HTML-based interfaces that allow your users to interact with the directory.

  • Development tools for application developers . If you plan to develop your own directory-enabled applications in-house, you may need to purchase development tools. Generally, LDAP client software development kits are available free of charge, but you may need to purchase compilers, graphical user interface (GUI) libraries, and other utility software necessary to develop your applications.

  • Directory-enabled applications . Along with the deployment of your directory, you may be able to deploy either new directory-enabled applications or upgrades to existing applications to make them directory-enabled. More information on directory-enabled applications can be found in Chapters 21, Developing New Applications, and 22, Directory-Enabling Existing Applications.

  • Backup and restore software . In some cases, backup devices are bundled with backup and restore utility software. Even if this is the case, you may decide to purchase a more comprehensive package ”for example, if you need to back up remote network nodes automatically to manage a tape carousel or jukebox.

Reducing Deployment Software Costs

As with hardware costs, software costs are often negotiable. Ask the vendor about various pricing options. Is the pricing per CPU? per server? per user? per entry? If multiple pricing options are available, one might be the best choice for your situation now, but another might benefit you down the road. Be sure to consider future growth when deciding on a pricing model.

Often you can obtain better pricing by purchasing additional software from the vendor at the same time. Take the time to find out whether your organization is in (or is planning) negotiations with the vendor over other software. A vendor will often provide more favorable pricing when multiple products are being purchased.

   


Understanding and Deploying LDAP Directory Services
Understanding and Deploying LDAP Directory Services (2nd Edition)
ISBN: 0672323168
EAN: 2147483647
Year: 2002
Pages: 242

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net