--On Monday, April 08, 2013 4:49 AM -0700 Howard Chu hyc@symas.com wrote:
Saša-Stjepan Bakša wrote:
Hi,
Maybe this is not the best way to ask but I would like to get some performance expectations or maybe suggestions how to improve performance. I do have relatively long experience with OpenLDAP as a precompiled package and with much less users so performance was not an issue for those installations.
Now I need to put few million users (now one million for test), custom tailored schema and search performance is crucial but also modify performance is big issue. Before MDB I have used HDB as backend.
What to do to improve write part of performance or performance in general (when adding data – from time to time – OpenLDAP stalls in a way)? Just around 5 add/mod operations during that time then it continue with much higher speed.
I have used many different sources to find out other peoples experience and I didn't choose to write to list lightly but I really need some help/hints.
There's nothing particular to LMDB to tune. But if you're seeing pauses due to disk I/O, as your iotop output seems to indicate, you might want to look into using a different I/O scheduler.
Not quite true. On Linux, I suggest setting the olcDbFlags as follows:
olcDbEnvFlags: writemap olcDbEnvFlags: nometasync
With those flags set, writes are 65x faster for me with back-mdb than they are with back-hdb/back-bdb.
--Quanah
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Quanah Gibson-Mount Sr. Member of Technical Staff Zimbra, Inc A Division of VMware, Inc. -------------------- Zimbra :: the leader in open source messaging and collaboration