a few back-bdb tuning questions

["matthew sporleder" <msporleder@gmail.com>]

I am using openldap 2.3.21 and bdb 4.4.20 (both compiled 64-bit) on solaris 10.

I followed (How do I determine the proper BDB/HDB database cache
size?) http://www.openldap.org/faq/data/cache/1075.html and saw the
note:
"I don't have enough free RAM to hold all the 800MB id2entry data, so
4MB is good enough."
And I found my number (around 30MB), which got me -great- read performance.

(so far I have my sun v120 upto 750+ BINDS/second using slamd and a
few thousand test accounts.  Although, when I turned on logging, it
went down to 350/second)

Well.. what if you do have enough ram?  Do you just set a huge cache
size, and it will eventually grab the whole thing?  Do I need to
include my indexes and other things in that memory calculation, or
just the id2entry?

The man page mentions that hdb needs a very large idlcachesize
relative to the cachesize.  What's the bdb recommendation on this?

When I checkpoint and use DB_LOG_AUTOREMOVE, what am I losing?  The
old transactions that have already been written to the database on
disk?  This would mean that my log.### are all active, correct?  Since
the old ones would have been deleted.

And can multiple subordinate databases (I didn't find a lot of
documentation about subordinate, by the way.  Shouldn't that be in
slapd.conf(5)?) share the same set_lg_dir?  Or should they be
separated into directories of their own?

Thanks,
_Matt