Re: bdb backend - reliable or not?

[Atom Powers <apowers@digipen.edu>]

Tomasz Chmielewski wrote:
> Unfortunately, the choice was a disaster - a couple of tests showed that 
> after powering off the server, OpenLDAP is not able to start anymore - 
> all I see in logs is a single message (loglevel 256):
>
> bdb_db_open: unclean shutdown detected; attempting recovery.
>
> And that's it, it never recovers.

As others have mentioned, you need to run `db_recover` on your database.

> On the other hand, I didn't have problems with ldbm on 2.3.6, or on any 
> older OpenLDAP version, so can one conclude that ldbm is more reliable 
> and crash-resistant?

More crash-resistant? Probably. BDB has a lot of performance features, 
some of which make it more fragile to system instability. I think you 
will find that almost all "decent" databases, and many other 
applications including the file system itself, have problems with 
unclean shutdowns.

> Will an upgrade to 2.3.24 solve my problems with bdb, or shall I revert 
> back to ldbm?

Don't use ldbm, unless you have a powerful server and a small number of 
users; and don't mind getting left out of future releases.

> Performance is not an issue here, databases are relatively small.
> What is important is the ability to survive unexpected system 
> crash/poweroff.

Then put the db_recover command in your start-up script, and/or tune BDB 
so that it can survive a crash more easily. But if you are experiencing 
unexpected crash/poweroff I'd say you have more serious issues than 
whether to use ldbm or bdb.

--
Perfection is just a word I use occasionally with mustard.
--Atom Powers--
Systems Administrator
DigiPen Institute of Technology
(425) 895-4443