Re: clarifications on cachesize, preferred db, et. al. from admin guide

[Quanah Gibson-Mount <quanah@zimbra.com>]

--On Thursday, April 07, 2011 6:46 PM -0500 Tim Mooney 
<Tim.Mooney@ndsu.edu> wrote:

> - Admin Guide, section 21.4.1.1.  The tuning chapter is a godsend and

[snip]

> Every single one of my index .bdb files is of type Btree, though, not
> Hash.  Is that section of the docs outdated, and all indexed attributes
> are now in Btree databases (for back-bdb and presumably back-hdb), or am
> I fundamentally misunderstanding what the index-related cache calculations
> are saying?

They are btrees.  You can find this is corrected in the FAQ:

<http://www.openldap.org/faq/data/cache/1075.html>

Specifically where it says:

Also, in OpenLDAP 2.2 onward, all of the indexes use B-trees, there are no 
more Hash database files. So just use the B-tree information above and 
ignore this Hash discussion.

> If you agree that it would be useful to explicitly list which backends
> would block the use of slapd-config and someone can provide me with the
> list of blockers, I would be happy to file an ITS and provide a patch to
> the current docs to spell things out.  I personally think it will help
> adoption of slapd-config.

Check against OpenLDAP 2.4.25.  I believe nearly all backends and overlays 
support slapd-config now.

> - man page for slapd.backends(5).  The man page entry states that
> bdb is the preferred backend.  I've seen enough hints and comments on
> the mailing list to suggest that it will eventually be supplanted by hdb.
> How soon is that going to happen (2.5?), and is it worth mentioning that
> hdb is as good as bdb now and will be the new preferred backend soon?
> Again, I'll submit the ITS with the doc patch if it's worth making that
> assertion in the docs now.

It was done with OpenLDAP 2.4.  The man page needs updating.

> - Admin Guide, chapter 21.  The tuning chapter doesn't mention the
> potential benefits of using an alternate memory allocator on Linux, as
> Quanah clued me in to on the mailing list last month.  Should it?  If
> people feel it would be worthwhile to mention, I would be happy to write
> the first draft and supply the patch in an ITS.

Probably.  It doesn't just apply to Linux.  It applies to all *nix systems.

> - Admin Guide, chapter 21.  The tuning chapter doesn't mention the
> potential benefits of using sysv shared memory vs. mmap'ed files on
> some platforms.  Should it?  Same offer for documentation patch applies,
> though I expect this one will need more feedback from the experts.

Do you mean the shared memory keys, or something else?

--Quanah

--

Quanah Gibson-Mount
Sr. Member of Technical Staff
Zimbra, Inc
A Division of VMware, Inc.
--------------------
Zimbra ::  the leader in open source messaging and collaboration