Dan, Swapping over to a vector clock based OT for federation has both upsides and downsides. The upside is that the document ownership is distributed. The downside is that the document ownership is distributed.
If everyone can agree up front what the valid modifications to a document are, including such fun and games as access control lists and the like, and everyone implements the same rules, exactly, then maybe it will work. One misstep and we have failure to converge nightmares that require debugging across multiple hosts. On the flip side, by having exactly one master, then all the rules around acceptable edits only have to live in one place, and can be changed both on a document by document basis, and over time, enabling system growth and change. The cost of this adaptability to change is that if a host disappears, the conversations that host was hosting are now toast. In short, I'm not completely sold that we can implement a vector clock based OT for federation and have it stable in the face of both bugs and future feature requests. brett On Sun, Jan 31, 2010 at 7:15 PM, Daniel Paull <[email protected]> wrote: > It's more than just an option - it's the only clear path forward. > Hopefully Dan Peterson and crew understand that. > > Cheers, > > Dan > > On Jan 31, 12:55 pm, Brett Morgan <[email protected]> wrote: >> Dan, >> >> An option is to use a variant of OT that uses a vector clock instead >> of the current single master OT. >> >> The fun thing would be that using a vector clock OT would even help >> out in the construction of fault tolerant Wave hosts, instead of >> having single points of failure inside the data center. >> >> brett >> >> >> >> >> >> On Sat, Jan 30, 2010 at 12:45 AM, Dan Peterson <[email protected]> wrote: >> > Agreed. This is an area I've been thinking about lately -- the electing a >> > new master scheme is appealing, but then what do you do when the original >> > master returns to the rest of the network (e.g. the uplink that was severed >> > is restored, then there'd be 2 servers that think they are master)? >> > As an alternative scenario, I suppose the wave client UI could encourage a >> > "fork" of the wave conversation -- copying the latest version of the >> > contents into a new wavelet on the non-dead wave provider. Of course, forks >> > are effectively duplicate content, so not so ideal. >> > -Dan >> >> > On Sat, Jan 30, 2010 at 12:36 AM, Torben Weis <[email protected]> >> > wrote: >> >> >> Hi, >> >> I fear it is not as easy as assigning it to missing FedOne features. >> >> If the master wave server breaks you need some other server to take >> >> over. But the domain name of the broken server is encoded in the wavelet >> >> URIs which are encoded (i.e. signed and hashed) inside the deltas. Thus, >> >> you >> >> cannot simply replace the wave server without taking care of the >> >> cryptographic problems. >> >> Even if this is dealt with, how do you efficiently vote on a new master >> >> server? It must not happen that at any time there is doubt about the >> >> master >> >> server (i.e. several clients deem different servers to be the master). >> >> Wave's OT cannot handle such a scenario. There are peer-to-peer OT >> >> concepts >> >> which can deal with it, but wave does not currently. >> >> I think this is a really interesting research question, but the solution >> >> will not be all too easy. >> >> This being said, even normal federation is complex enough :-) >> >> Cheers >> >> Torben >> >> 2010/1/29 Mickaël Rémond <[email protected]> >> >> >>> Hello, >> >> >>> Le 29 janv. 2010 à 13:17, chiang a écrit : >> >> >>> > Hi all, >> >> >>> > This could already have been a known deficiency in the federation >> >>> > architecture, but I would like to enquire if it is by design that we >> >>> > have authoritative or master wave servers for a particular wave? As >> >>> > I've just found out that if the Fedone wave server (which hosts a >> >>> > master copy of my initiating wave) goes down or losses all the waves, >> >>> > the Fedone wave server does not recover the wave from wavesandbox, >> >>> > which also has a copy of the wave. I initially thought wave servers >> >>> > federation is supposed to be scalable, and resilient... >> >> >>> Fedone is an example implementation, not a production ready wave server. >> >>> For example, it still miss the storage engine, is not clustered etc. >> >>> So this limitation is not by design but simply a not-yet-implemented >> >>> feature. >> >> >>> Having an authoritative server for every wave seems a good and needed >> >>> approach for the Wave protocol itself. >> >> >>> -- >> >>> Mickaël Rémond >> >>> http://www.process-one.net/ >> >> >>> -- >> >>> You received this message because you are subscribed to the Google Groups >> >>> "Wave Protocol" group. >> >>> To post to this group, send email to [email protected]. >> >>> To unsubscribe from this group, send email to >> >>> [email protected]. >> >>> For more options, visit this group at >> >>>http://groups.google.com/group/wave-protocol?hl=en. >> >> >> -- >> >> You received this message because you are subscribed to the Google Groups >> >> "Wave Protocol" group. >> >> To post to this group, send email to [email protected]. >> >> To unsubscribe from this group, send email to >> >> [email protected]. >> >> For more options, visit this group at >> >>http://groups.google.com/group/wave-protocol?hl=en. >> >> > -- >> > You received this message because you are subscribed to the Google Groups >> > "Wave Protocol" group. >> > To post to this group, send email to [email protected]. >> > To unsubscribe from this group, send email to >> > [email protected]. >> > For more options, visit this group at >> >http://groups.google.com/group/wave-protocol?hl=en. >> >> -- >> Brett Morganhttp://domesticmouse.livejournal.com/ > > -- > You received this message because you are subscribed to the Google Groups > "Wave Protocol" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/wave-protocol?hl=en. > > -- Brett Morgan http://domesticmouse.livejournal.com/ -- You received this message because you are subscribed to the Google Groups "Wave Protocol" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/wave-protocol?hl=en.
