The number of machines and software licenses required will depend on the topology of the directory infrastructure and how much backup is required. Assuming the requirements dictate response times of a few seconds and twenty four by seven availability then backup for every server containing master data will be necessary. A single directory server should be able to cope with a database consisting of several thousand entries. Though this, of course, is influenced by the power of the hardware and the particular implementation used. As a very rough guideline expect to pay about 5,920 ECU(£4000) for a hardware platform (including OS costs and other support software) that will support 10,000 entries. A server license will cost between 7,401 ECU(£500) and 1,480 ECU (£1000), although the cost is likely to scale downwards as license numbers increase. For a single site, one main and one backup server would put the server cost at around 14,800 ECU(£10,000). Scaling up linearly, a larger organization with five sites may need to spend 74,009 ECU (£50,000). Be careful to include client costs in the capital expenditure. Client software should be relatively inexpensive and may well be as little as 10 ECU (£14.80)per head under a site licensing scheme. Again, costs will vary and depend on numbers. As well as user access software, you will need to consider the requirement for update interfaces that will be used by administrators to manage the directory database.
Database integrity will demand a consistent level of manpower. One or more people dedicated to the task of managing the service may be necessary. The exact level of effort needed will depend on the size and nature of the organization. Estimating this will be difficult and so it maybe useful to postpone the formation of a management team until some experience has been gathered. This approach could lead to a overloading of existing staff in the initial phases while data is verified through usage. In all cases procedures for directory update should be defined. This means advertising a contact point used to channel requests for change and assigning responsibility for the task. The management duty is extremely important and should not be underestimated! Data management will involve software costs. Data synchronization tools, if available, will force expenditure. If suitable tools are not available, then a degree of in-house effort to develop, for example, data conversion tools could be called for.