:)... You are not the only one who faced this kind of problem !
2009/10/15 Zhang Weiwu <[email protected]>: > I found the problem. Stupid problem, this took us several days! > > Since it has been so many days, I quote the full original question for > your reference, see the bottom for the last jigsaw of the puzzle > > Zhang Weiwu wrote: >> We have a development server 'emerson' with roughly one third of the >> performance of our productional server 'bossdog', it runs ldap query 10 >> times faster than the productional server. I checked everything I can to >> find out the difference, it seems both are equally configured. >> >> Test method: >> >> emerson:~# time for (( i=0; i<100; i++)); do ldapsearch -xD >> cn=manager,dc=eoa,dc=cn -w masked -b ou=contacts,ou=realss.com,dc=eoa,dc=cn >> '(uidNumber=7)' dn; done; >> [snip] >> # zhangweiwu, contacts, realss.com, eoa.cn >> dn: uid=zhangweiwu,ou=contacts,ou=realss.com,dc=eoa,dc=cn >> >> # search result >> search: 2 >> result: 0 Success >> >> # numResponses: 2 >> # numEntries: 1 >> >> real 0m1.047s >> user 0m0.320s >> sys 0m0.352s >> >> bossdog:~# time for (( i=0; i<100; i++)); do ldapsearch -xD >> cn=manager,dc=eoa,dc=cn -w masked -b ou=contacts,ou=realss.com,dc=eoa,dc=cn >> '(uidNumber=7)' dn; done; >> [snip] >> >> real 0m41.790s >> user 0m0.232s >> sys 0m0.464s >> >> >> What I have compared: >> >> 1. Both server uses Debian Lenney >> 2. Both server have same DB_CONFIG in /var/lib/ldap >> 3. Both server have same ACL settings. In fact we tried to reduce the >> ACL setting on the slow preforming productional server without >> improvement result. >> 4. Both server uses bdb >> 5. Compare syslog at log level 256 both server produce same log messages >> 6. The productional server shows harddisk is twice as fast as >> development server (hdparm), free memory more than the development >> server, and its dual-core xeon cpu should outperform the VIA CPU >> used in the development server, yet slower. The productional >> server average load is 0.5 which is not high for dual-CPU (with >> hyperthreading display as 4 CPUs to Linux). >> 7. Productional server DB is then re-built (by rm -rf & slapadd) >> without noticeable change in performance. >> >> This performance difference resulted the productional server user >> interface much slower than user's patience. >> >> What would you check further in this case? Thanks in advance > > The problem is we have been looking into openldap and system > resource/kernel so much that we forgot other software directly related > to performance. There had been something wrong made syslog low > performance, change loglevel to none instantly solves the problem. > > -- Regards, Cordialement, Emmanuel Lécharny www.iktek.com
