On 08.10.2015 10:29, Alberto Garcia wrote: > On Thu 08 Oct 2015 08:15:25 AM CEST, Markus Armbruster wrote: >>> For the second point, you should also consider how useful this >>> feature is to management tools. Just being able to remove and attach >>> children from a quorum node seems very useful on its own. I don't see >>> why we should wait for having support for other block drivers; also, >>> for most block drivers there is no meaningful way of adding or >>> removing children as nicely as that is possible for quorum. >> >> Okay, this is an argument I might be able to buy. > > Note that if we want to make this interface stable there's one use case > missing: there's currently no way to change the vote threshold.
Besides what Kevin said: If you add a new function, that would be
independent from these two functions. If want to add it as an optional
parameter to blockdev-add-child so the change is done atomically, that
wouldn't be an incompatible interface change either.
Max
> This is maybe not so important for the COLO use case, but for the
> general case of adding and removing children from a quorum node having
> the possibility to change the threshold makes a lot of sense.
>
> That would probably require a its own API ('quorum-set-threshold' or
> something like that) so I don't think it has an effect on these
> child-add and child-del commands, but I wanted to mention it here anyway
> in case someone sees something that I'm overlooking.
>
> Berto
>
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