Tuning nsslapd-dbcachesize on Solaris

[gholbert at broadcom.com (George Holbert)]

When tuning FDS on a Solaris machine, I've heard two different 
suggestions about nsslapd-dbcachesize:
1. Decrease nsslapd-dbcachesize, and instead rely on Solaris' built-in 
filesystem cache which performs better.
2. Tune nsslapd-dbcachesize up to a value that is at least as large as 
the size of your backend LDBM database.

To know for sure which works best in my case, I'll need to test both of 
course.  But, does anyone have any thoughts or prior experience on which 
of the above options performs better?

Thanks a lot,
-- George