Lotus Notes/Domino 6 and above uses LZ1 compression for file attachments.
LZ1 stands for "Lempel-Zev class 1"; it is a different method
of compression from that of the Huffman algorithm, which is the method
by which Notes/Domino R5 compresses attachments.
Because LZ1 compression can save a considerable amount of disk space, it
is favored over the Huffman method. However, if the LZ1 compression option
is set on a Domino 6 and above database, a Notes 5 client will be unable
to read the compression. The Domino server converts LZ1 to Huffman compression
for the Notes 5 client. This affects server performance. LZ1 compression
should be exclusively implemented in a Lotus Notes/Domino 6 and above environment.
This property is disabled upon database creation
Enable 'Use LZ1 compression
on attachments' option in the database
properties. Do this for multiple files at once via the Domino Administrator
from the 'Files' tab.
Is LZ1 Compression in Notes/Domino 6.x?
Domino Configuration Tuner:
This setting is included in the DCT
catalog of best practices.