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. 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