Red Hat Directory Server 7.1 Performance Tuning and Sizing Guidelines

Please note, to control percentage of total entries to be cached, use attribute nsslapd-cachesize. To cache

0% of total entries, set nsslapd-cachesizeto 1(minimum value). From Table 4, you can see that as number of entries can be cached in the entry cache increases, the exact search throughput increases too.

Number of Entries in the Database

DirMark Search performance

DirMark Search performance

 

(cachememsize: 100% or max

(cachememsize: default

 

cachesize: -1

cachesize: 1

 

dbcachesize: 100% or max)

dbcachesize: 100% or max)

100

14642.13

8548.93

10,000

13808.97

8164.30

100,000

13135.43

7993.63

250,000

12986.10

7906.10

500,000

13230.17

7830.73

1,000,000

12846.54

7918.02

5,242,885

12289.70

7895.90

10,485,760

11710.23

7544.43

Table 5: Performance difference based on different nsslapd-cachesize/nsslapd-cachememsizefor different size of databases. Measured on a Montecito-based test configuration 8 CPUs @1.6GMHz each.

From Table 5 you can see that if all the entries are cached in the entry cache, and if all the pages are cached in the dbcache, then the search throughput is close to each other no matter how big the database is. On the other hand, if none of the entries are cached in the entry cache, the search throughputs for different sizes of databases are close to each other too. So it turns out that if dbcache is big enough to hold all the pages, then the average exact search throughput of any size of database with RHDS version 7.1 will be between around 8060 operations/second to 13442 operations/second depending on how big the entrycache is.

Data Collection 5: (Access Log On vs. Access Log Off)

This set of data is collected to help us understand how logging can affect the performance.

•Server: Montecito-based test configuration 8 CPUs @1.6GHz each

•#of entries: 100K

•RHDS parameter settings: dbcachesize and cachememsize are big enough to cache all the entries, and nsslapd-threadnumberis set to 6.

Access log on or off DirMark Search performance

ON12727.20

OFF13209.48

Table 6: RHDS7.1 performance difference when access log is turned on or off.

From Table 6, you can see that by turning the access log off, the exact search throughput can increase about 4% in a Montecito-based test bed.

Data Collection 6: (SSL Connection Enabled vs. SSL Connection Disabled)

This set of data is collected to help us understand the performance impact if SSL connection is enabled.

•Server: Montecito-based test configuration 8 CPUs @1.6GHz each

•#of entries: 10K

•RHDS parameter settings: assume dbcachesize and cachememsize are big enough to cache all the entries. nsslapd-threadnumberis set to 6.

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