Service manual

Sizing Physical Memory
84 Sun ONE Directory Server Installation and Tuning Guide • June 2003
Additionally, allocate memory for general system overhead and normal
administrative use. A first estimate for this amount,
systemOverhead,shouldbeat
least several hundred megabytes, or 10 percent of the total physical memory,
whichever is greater. The goal is to allocate enough space for
systemOverhead that
the system avoids swapping pages in and out of memory while in production.
The total memory needed by the operating system,
systemTotal,canthenbe
estimated as follows.
systemTotal = systemBase + systemOverhead
Sizing Total Memory
Given slapdTotal and systemTotal estimates from the preceding sections,
estimate the total memory needed,
totalRAM.
totalRAM = slapdTotal + systemTotal
Notice totalRAM is an estimate of the total memory needed, including the
assumption that the system is dedicated to the Directory Server process, and
including estimated memory use for all other applications and services expected to
run on the system.
Dealing With Insufficient Memory
In many cases, it is not cost effective to provide enoughmemory to cache all data
used by Directory Server.
At minimum, equip the server withenough memory that running Directory Server
does not cause constant page swapping. Constant page swapping has a strong
negative performance impact.You may use utilities such as
vmstat(1M) on Solaris
and other systems to view memory statistics before and after starting Directory
Server and priming the entry cache. Unsupported utilities available separately
such as
MemTool for Solaris systems can be useful in monitoring how memory is
used and allocated when applications are running on a test system.
NOTE For top performance, dedicate the system running Directory Server
to this service only.
If you must run other applications orservices, monitor the memory
they use as well when sizing total memory required.