LDAP-UX Client Services B.04.00 with Microsoft Windows 2000/2003 Active Directory Administrator's Guide

Administering LDAP-UX Client Services
Client Daemon Performance
Chapter 4120
Client Daemon Performance
Compared to previous networked name service systems, LDAP directory
servers support a number of new features. And the general purpose
nature of LDAP allows it to support a variety of applications, beyond
those just used by a networked OS. Although directory servers have
excellent performance and scalability, the addition of these features,
such as security, means that directory applications will benefit from a
design that considers performance requirements. In order to maximize
of the number of HP-UX clients that can be supported by an LDAP
directory server, and also improve client response, the ldapclientd
daemon supports both data caching and persistent network connections.
Their use, benefits and side-effects are described below.
ldapclientd Caching
Caching LDAP data locally allows for much greater response time for
name service operations. Caching means that data that has been
recently retrieved from the directory server will be retrieved from a local
store, instead of the directory server. Caching greatly reduces both
directory server load and network usage. For example, when a user logs
into the system, the OS typically needs to enquire about his/her account
several times in the login process. This occurs as the OS identifies the
user, gathers account information and authenticates the user. And
further requests often occur as the account starts up new applications
once a session is established. With caching, generally only one or two
LDAP operations are required.
Caching is also critical to support certain types of applications that make
frequent demands on the name service system, either because they are
malfunctioning or need this specific type of information frequently.
ldapclientd also supports what is known as a negative cache. This type
of cache is used to store meta-data about non-existent information. For
example, if an application requests information about an account that
does not exist, the directory server will not return an entry, and that
negative result will be stored in a cache. Intuitively this type of cache
would seem to be un-necessary. However, applications exist that may
perform these operations frequently, either on purpose or because they
are malfunctioning. For example, if a file is created with a group ID that