HP-UX Directory Server 8.1 Performance Tuning and Sizing Guidelines

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Equation 1: Estimate Size of Database Cache
dbcachesize = SUM(allDB4files)
Note: Equation 1 gives you a very rough estimation for dbcachesize. When estimating
database cache size, include only those database (db4) files that your operations ne
ed. For
example, if your directory server only needs to support exact search requests on the “cn”
attribute, you may need just 354MB dbcache instead of 685MB dbcache which is the sum of all
database (db4) files for the 250K databases. For more information about how to manage
indexes, see the
HP-UX Directory Server administrator guide.
Figure 2 shows performance results using the Montvale-based test configuration (8 CPUs@1.6GHz)
measured against different values of the nsslapd-dbcachesize parameter.
Figure 2: Performance based on nsslapd-dbcachesize
nsslapd-cachememsize and nsslapd-cachesize
The nsslapd-cachememsize and nsslapd-cachesize parameters determine the size of the
entry cache, which caches each entry that has been accessed in memory. The nsslapd-
cachememsize determines how many bytes of entries can be cached in memory. The nsslapd-
cachesize parameter determines how many entries can be cached in memory. These parameters
are described as follows in the
HP-UX Directory Server configuration, command, and file reference.
Refer to the document for more information.
nsslapd-cachememsize:
This performance tuning attribute specifies the cache size in terms of available memory
space. The simplest method is limiting cache size in terms of memory occupied. Activating
automatic cache resizing overrides this attribute, replacing these values with its own guessed
values at a later stage of the server startup. Attempting to set a value that is not a number or is
too big for a 32-bit signed integer returns an LDAP_UNWILLING_TO_PERFORM error message
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
0 100 200 300 400 500
operations/sec
dbcache in 1000000 bytes
250k, 2 dual-core CPUs