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

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

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


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  Is that section of the docs outdated, and all indexed attributes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:


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 Gibson-Mount
Sr. Member of Technical Staff
Zimbra, Inc
A Division of VMware, Inc.
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