for very large machines (>10Gbit) it is still useful
to have parallelism for uploads because we're actually
bound by getting new pieces from the satellite, so doing
that in parallel provides a big win.
this change adds back that flag to exist for uploads, and
removes the backwards compatibility code for the flag with
the maximum-concurrent-pieces as they are now independent.
the upload code parallelism story is now this:
- each object is a transfer
- each transfer happens in N parts (size dynamically
chosen to avoid having >10000 parts)
- each part can happen in parallel up to the limit
specified
- each parallel part can have up to the limit of
max concurrent pieces and segments
this change also changes some defaults to be better.
- the connection pool capacity now takes into acount
transfers, parallelism and max concurrent pieces
- the default smallest part size is 1GiB to allow the
new upload code path to upload multiple segments
Change-Id: Iff6709ae73425fbc2858ed360faa2d3ece297c2d