> As you might know that the Clearview vanity naming component is
> proposing to add a "-l" option to specify the link of various dladm
> subcommands. For example, "dladm create-vlan -l net0 -v 28 vlan1" is to
> create a VLAN vlan1 over link net0.
>
> But then we found that "-l" is already used in the create-aggr
> subcommand to specify the LACP mode.
>
> We can think of several options to solve this problem:
>
> 1. we can choose not to introduce another option, but simply use the
> original "-d" option to specify the link. Although it might be somewhat
> misleading because the link is not really a *d*evice, but from the user's
> perspective, it might not necessarily a bad thing. Plus "-d" is used in
> snoop to specify a link anyway.
>
> 2. use "-l" to specify both link and the LACP mode. Because link name
> always ends with a digit, so that we can differentiate these two cases.
>
> 3. use "-L" to specify the link, and leave "-l" to specify the LACP mode. I
> personally don't like this option.
As the person who suggested (2), let me clarify my suggestion: it was that
we change the documentation create-aggr and modify-aggr to state that "-L"
changes the LACP mode, but that for compatibility, we continue to quietly
recognize "-l off", "-l active", and "-l passive" as synonyms for "-L
off", "-L active" and "-L passive". My reasoning for this is threefold:
1. As Cathy mentioned, we will be making a split -- especially apparent
in dladm -- between devices and links. It is possible (though not
recommended) for an administrator to have two devices, A and B, with
link names B and A. Having them to specify "-d A" and actually end
up with link B fails the principle of least surprise. I would rather
have "-d A" remain a legacy way to refer to device A (regardless of
its link name), and "-l A" refer to link A (device B here). We would
of course encourage people to use "-l" in general with dladm.
2. Also related to the principle of least surprise, I'd like all dladm
subcommands that operate on links to use the same option letter. So
if we choose "-d" for create-aggr, I'd want to use "-d" across the
board. But then we risk deepening the confusion between links and
devices stated above -- and all to sidestep what seems to be a rarely
used option to a command that has only been available to customers
for a year or so. Since dladm will likely last for decades, that
doesn't seem like the right trade-off to me. Likewise, in a decade,
no one will remember that for a couple of S10 update releases, "-l"
was the documented way to set the LACP mode for create-aggr.
3. Speaking of consistency, show-aggr already uses -L to show LACP
information. So using -L to set LACP mode with create-aggr and
modify-aggr seems more consistent anyway.
--
meem
