--On Tuesday, January 15, 2013 3:21 PM -0200 Friedrich Locke friedrich.locke@gmail.com wrote:
Dear gentleman/madam,
as you may be aware i am having hard times trying to get qmail+ldap working on my OpenBSD 5.2 amd64. While after installation OLDAP works 100% (I am using BDB as backend). When i start qmail, every query sent by qmail to the OLDAP server increases memory up to a point OLDAP needs to be restarted.
I emailed misc@openbsd.org. I got responses. Here i pass them to the OLDAP developer: After some advice from Mr. Quanah, i gave up BDB and would like to give MDB a try. Here is what i got from the misc@openbsd.org
Hi Friedrich,
As per Howard Chu (Author of MDB, Primary OpenLDAP Developer):
------------------------------------------------------------- Full details are in the paper. http://www.openldap.org/pub/hyc/mdm-paper.pdf
MDB assumes a unified buffer cache. See section 3.1, references 17, 18, and 19.
Note that this requirement can be relaxed in the current version of the library. If you create the environment with the MDB_WRITEMAP option then all reads and writes are performed using mmap, so the file buffer cache is irrelevant. Of course then you lose the protection that the read-only map offers. -------------------------------------------------------------
I will note that I personally always set MDB_WRITEMAP in my deployments: zimbra@zre-ldap002:~$ ldapsearch -LLL -x -H ldapi:/// -D cn=config -W -b "olcDatabase={2}mdb,cn=config" -s base olcDbEnvFlags
dn: olcDatabase={2}mdb,cn=config olcDbEnvFlags: writemap olcDbEnvFlags: nometasync
I do this as the protections you lose are still better than any guarantee one ever had with using BDB (possible loss of the most recent transaction).
--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