Red Hat Directory Server 7.1 for HP-UX11i v2 Integrity System Performance Tuning and Sizing Guideline

Red Hat Directory Server 7.1 Performance Tuning and Sizing Guidelines
• Server: Montecito-based 8 CPUs @1.6 GHz
• #of entries: 250K
• RHDS parameter settings: set cachememsize big enough to cache all the entries. dbcachesize is tuned as
shown in Table 3, nsslapd-threadnumber is set to 6
dbcachesize DirMark Exact Search
Performance
500,000 12155.43
1,000,000 12400.40
1,500,000 12412.60
2,000,000 12446.90
4,000,000 12670.00
10,000,000 12935.50
50,000,000 12962.33
100,000,000 13117.60
200,000,000 13013.47
300,000,000 12986.17
400,000,000 13033.00
Table 3: RHDS7.1 performance difference based on different nsslapd-dbcachesize.
Because there is no particular method to determine how big the dbcache is at any given time, data shown in Table 3
is collected based on the full entry cache and different settings of dbcachesize starting from the minimum value of
500,000. When dbcachesize is set to 300,000,000, dbcachehitratio is very close to 100%, thus we can assume
that the dbcache is big enough to hold all the pages. Please note, as dbcachesize increases from 500,000 to
300,000,000 the search throughput only increased 6.8% in our Montecito-based test bed with RHDS 7.1.
Comparing to entrycache size optimization, the size change with dbcache is insignificant. As entrycache size
increases from 0% to 100%, the throughput increased about 66%. (As shown Table 4). Thus it appears that
entrycache has more impact on performance than dbcache. In the performance test, the entries in the LDAP
database are accessed uniformly throughout the test. This characteristic means that increasing the entrycache size
will provide the most performance improvement for the test. However, in practical applications, this may not
always hold true. If a small subset of all the entries tends to be accessed much more frequently than the rest, then
priority to the dbcache instead of the entrycache can be given if memory constraints require a tradeoff.
Data collection 4: (Different entrycache setting)
This set of data is collected to help us understand how entrycache affects the performance.
• Server: Montecito-based test configuration 8 CPUs @1.6GHz
• #of entries: 250K
• RHDS parameter settings: set dbcachesize big enough to cache all the pages. cachesize is tuned as shown in
Table 4, cachememsize is tuned big enough to cache all the entries, nsslapd-threadnumber is set
to 6
% of total database entries
(nsslapd-cachesize)
DirMark Exact Search Performance
0% of total entries 7853.53
20% of total entries 7005.90
40% of total entries 7831.47
60% of total entries 9316.37
80% of total entries 11112.33
100% of total entries 13017.20
Table 4: RHDS7.1 performance difference based on different nsslapd-cachesize settings.
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