Service manual

Sizing Disk Subsystems
Chapter 4 Hardware Sizing 85
If the system cannot accommodate additional memory, yet you continue to observe
constant page swapping, reduce the size of the database and entry caches. Running
out of swap space can cause the Directory Serverto crash.
Refer to Chapter 6, “TuningCache Sizes”, for a discussion of the alternatives
available when providing adequate physical memory to cache all directory data is
not an option.
Sizing Disk Subsystems
Disk use and I/O capabilities can strongly impact performance. Especially for a
deployment supporting large numbers of modifications, the disk subsystem can
become an I/O bottleneck. This section offers recommendations for estimating
overall disk capacity for a Directory Server instance, and for alleviating disk I/O
bottlenecks.
Refer to Chapter 8, “Tuning Logging”, for more information on alleviating disk
I/O bottlenecks.
Sizing Directory Suffixes
Disk space requirements for a suffix depend not only on the size and number of
entries in the directory, but also on the directory configuration and in particular
how the suffix is indexed. To gauge disk space needed for a large deployment,
perform the following steps:
1. Generate LDIF for three representative sets of entries like those expected for
deployment, one of 10,000 entries, one of 100,000, one of 1,000,000.
Generated entries should reflect not only the mix of entry types (users, groups,
roles, entries for extended schema) expected, but also the average size of
individual attribute values, especially if single large attribute values such as
userCertificate and jpegPhoto are expected.
2. Configure an instance of Directory Server as expected for deployment.
In particular, index the database as you would for the production directory. If
you expect to add indexes later, expect to have to add space for those indexes
as well.
3. Load each set of entries, recording the disk space used for each set.
4. Graph the results to extrapolate estimated suffix size for deployment.