What?

I have a use case where I need to load 1-2GB of data in a memory constrained environment. The application only has around 800MiB, but around 600 is allocated to application heap. The load time for this application is taking around 15 minutes and I was wondering what parameters I can tune to speed this initial load. Also I do not have any guarantee on the ordering of the keys for this initial load. Looking at my disk, it seems that I have reached limits of my disk I/O, but I am not sure if there is something I can do to reduce disk I/O for the initial load.

I have set the following:

lmdb.nosync=true
lmdb.nometasync=true
lmdb.writemap=true
lmdb.mapasync=true
lmdb.nordahead=true

Possible things I have to try:

1. Open single transaction for bulk load. Is this possible with the memory constraints?
2. Reduce byte buffer allocation