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Re: slapd hangs doing large ldap (add|modify|delete)

First, please read:


then find my answers inline.

--On Tuesday, August 09, 2005 9:31 AM +0530 Thaths <thaths@gmail.com> wrote:

On 8/9/05, Quanah Gibson-Mount <quanah@stanford.edu> wrote:
--On Monday, August 08, 2005 6:35 PM +0530 Thaths <thaths@gmail.com>
> I would really like to deploy OpenLDAP throughout my 700-user network.
> However, slapd stops working from time to time randomly. When I run
> slapcat nothing happens and the command hangs. This is really
> frustrating me.
Have you done any logging?

> 1. Why does these hangs happen?

Have you configured slapd properly?

I am quite sure that I have. I am not doing anything extraordinary.

Okay. What is your entry cache setting? What is your idl cache setting?

Have you configured BDB properly?

How do I do this? I tried reading the README.DB_CONFIG but it is too obtuse for me to follow.

There is an entire FAQ entry at http://www.openldap.org/ about this.

You may also wish to read:






> 2. How can I avoid them?
Have you turned up logging?

No. I will try it with me next attempt.

Okay. It might not provide much information though.

> 3. Can I recover from such a hang when it happens? How?
db_recover, usually.

> I tried db_recover and it didn't solve the crash/hang. Here is the > output: > > jupiter:~# db_recover -c -v -h /var/lib/ldap > db_recover: Ignoring log file: /var/lib/ldap/log.0000000004: > unsupported log version 8

This indicates you are using the wrong version of db_recover. Note that sarge installs multiple versions of BDB, and that OpenLDAP in sarge uses BDB 4.2.52 + patches (and not BDB 4.3 which is the default db_recover) command.

According to the Debian package search, there is only one package - libdb2-util - that contains db_recover


Where do I get db_recover 4.2.52+patches for sarge?

Dunno, I'm not using Sarge's install of OpenLDAP. I do know, however, it is linked to BDB 4.2.52 and not BDB 4.3.

> If this is the stability level of OpenLDAP, I really hesitate to use
> it in a production environment.
OpenLDAP + BDB is rock stable for me, so I'm inclined to believe you have
other issues.  Although I will note that OpenLDAP 2.2.23 is several
releases behind (2.2.26 is stable, 2.2.27 is the current 2.2 release).

I was googling for this problem and it seems there might be issues with dbd and my filesystem being reiserfs. To complicate matters, my disks are also hardware raid mirrored. I think reiserfs could be complicating my problem. What filesystem are you using to get this rock stability?

I would rather not install from source. I prefer going with the deb
binary as it makes upgrading much easier.

Not really. You could simply build the latest source using the debian spec file. The fact that debian sticks to a particular release without providing new updates to it is problematic in my opinion. There is no issue going between minor releases of OpenLDAP (2.2.23 to 2.2.26).

I believe you are correct, however, that there is an issue with BDB and reiser FS. On debian (I build all my software from source), I use ext3 as my filesystem (with RAID).


Quanah Gibson-Mount
Principal Software Developer
ITSS/Shared Services
Stanford University
GnuPG Public Key: http://www.stanford.edu/~quanah/pgp.html

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