Symmetric vs. Asymmetric and some random thoughts

[julian_satran@il.ibm.com]

I would like to point out that the dead-lock situation described in several
posts by Costa and myself is mostly a result of sending at leisure
unsolicited data.

With an asymmetric scheme with a  single connection in which data and
commands follow
the same prescribed order the deadlock can be avoided - but then the closed
window for new
commands is more of a concern.

The one big disadvantage of the asymmetric scheme is IMHO the fact that
writes can't carry
immediate data - and that is a performance hit for software based
initiators that will
have to handle 3 i/o operations per small write where the symmetric scheme
required 2 i/os.

Julo