Typically, you define a maximum size for the storage pool.  The problem here
is that the TDP is different and Oracle does not preannounce the object
size.  So, I think it will get to 20GB fail and  then resend the object, but
TDP for Oracle may not be able to resend, thus it will just fail.  This is
just a stab at what may happen.  I have never seen it before.