I have been watching an initial TSM backup running for a long time now over
a WAN connection (100mbit/sec) and I keep seeing "compressed data grew"
followed  by a "Retry".  Does this mean that for every file that
compression increased the size (even 1%) the whole transfer is discarded
and it starts over again with the same file (presumably with compression
disabled)?  If so that is probably hurting my backup speed much more than
the compression ever improved it.  Is there any way to prevent this short
of adding one of these options for every type of compressible file?

EXCLUDE.COMPRESSION "*:\...\*.jpg"
EXCLUDE.COMPRESSION "*:\...\*.zip"