Here is my 1st try at a memory backed venti server. 
Use the files with current planport src/cmd/venti/srv directory.

The patch for lump.c is needed to avoid pulling in the bitrot from queuewrites.
The venti.conf file should not contain lines for bloom, isect and queuewrite.

If you write to arenas, you will need to rebuild the index, if you want to 
use venti again.

The expected memory footprint is now
 12 bytes per clump for leaf storage
   (could be shortened to 8, if the handling of type and size info is adapted)
 64 byte per trie node, the number of trie nodes is ca. 40% of the leaves.

Here is the storage output:
index=main
total arenas=200 active=160
total space=107,366,932,480 used=85,450,596,349
clumps=11,897,412 compressed clumps=6,912,817 data=152,536,838,549 compressed data=84,701,059,393

Startup time is about 2 Minutes.

wb.kloke@gmail.com