You have enough memory for 1.25 Gb of bdb cache? You don't post your machine spec so its difficult to say if that is sane, but make sure its not using lots of swap. I note that your bdb logs are on the same disk as your swap (and your syslogs presumably), so if you are swapping (or anything is logging heavily) that will have an impact on bdb writes.
Hm, interesting...
--Quanah
-- Quanah Gibson-Mount Principal Software Developer ITSS/Shared Services Stanford University GnuPG Public Key: http://www.stanford.edu/~quanah/pgp.html