Re: bdb backend - reliable or not?

[Howard Chu <hyc@symas.com>]

Owen DeLong wrote:
> This may not be the politically correct thing to say here, but, it is my
> experience and YMMV.
>
> BDB is very stable and reliable, once you get the right combination of
> configuration figured out.  There's lots of different things that need
> to be set up to get BDB stable and many of them are less than obvious
> in the installation process.
>
> Running db_recover before EVERY startup is safe and, in my experience,
> virtually necessary.  If the shutdown was clean, db_recover will quickly
> figure out that it doesn't have to do anything and move on.

As pointed out before, running db_recover is not needed for current 2.3 
releases.  Also, running it when it is not needed will wipe out the BDB 
cache unnecessarily, which will cause server performance to be slower 
while the cache gets re-seeded.
> Another important thing is to get DB_CONFIG set up correctly.
And as I've pointed out many times, in OpenLDAP, BDB does not use 
temporary files, so the set_tmp_dir directive is also unnecessary.
> Here is my DB_DONRIG file:
>
> # In Memory Cache Size
> set_cachesize   0       8388608         0
>
> # Database Flags
> #set_flags      DB_TXN_NOSYNC   # Don't immediately flush txn logs. 
> Dangerous
>
> # Log Values
> set_lg_regionmax        1048576
> set_lg_max              10485760
> set_lg_bsize            2097152
> set_lg_dir              /var/lib/ldap/bdb-logs
>
> # Temporary file location
> set_tmp_dir             /tmp
>
>
> Hope that helps.
>
> Owen
--
 -- Howard Chu
 Chief Architect, Symas Corp.  http://www.symas.com
 Director, Highland Sun        http://highlandsun.com/hyc
 OpenLDAP Core Team            http://www.openldap.org/project/