RE: How to improve performance with MDB backend?

[Chris Card <ctcard@hotmail.com>]

----------------------------------------
> Date: Thu, 18 Apr 2013 09:13:42 -0700
> From: quanah@zimbra.com
> To: ctcard@hotmail.com; openldap-technical@openldap.org
> Subject: RE: How to improve performance with MDB backend?
>
> --On Thursday, April 18, 2013 3:59 PM +0000 Chris Card <ctcard@hotmail.com>
> wrote:
>
> > Maybe MDB performance relative to BDB degrades as the database get
> > bigger. From your wiki page: "This particular client has 25,208 entries
> > in their LDAP database". My test database has over 3 million entries
> > (production has nearly 7 million), which take about 20 minutes to slapadd
> > into MDB initially. My machine has 128 Gb RAM and the MDB db size
> > is 429496729600, so slapd can't map the whole db file into RAM.
>
> How big is your DB when loaded vs maxsize? If you are using writemap, the
> maxsize *must* be larger than the DB size. Also, what OpenLDAP version are
> you using? That's always important to note.
>
I'm using openldap 2.4.35.

olcDbMaxSize: 429496729600
and that's the size of the file on the disk too:

-rw------- 1 ldap ldap 429496729600 Apr 18 16:52 data.mdb
-rw------- 1 ldap ldap         8192 Apr 18 17:52 lock.mdb

The size of the db files for BDB is about 22 Gb.

Chris