I'm not confident it won't work. I'm confident that it's not tested and any dev in any change someone is not paying attention to can make it not work. So to say it will work or to even count on it working is silly. The are tons of behavior changes beyond what's in ZK that could mess with rolling upgrades. We find issues doing non rolling upgrades on *point* releases in my experience.
The only way you will ever know is to test it out when the release happens, and even then, not every issue is easily caught by a simple test. Commands can come in during the rolling upgrade, certain features can be broken, etc, etc. I would like to support rolling updates on point releases, that's def a goal, even that is still a bit of prayer as it's not properly tested and it can depend on what version you coming from and going to. - Mark On Tue, Feb 23, 2016 at 1:54 PM Shai Erera <ser...@gmail.com> wrote: > Mark, I understand that we currently don't have any other promises :). I > asked in case you happen to know that "oh yeah, in 6.0 we've changed ZK to > refer to /solr_collections instead of /collections" (I wish it would be > *that* trivial :)). > > If you don't have a list that's fine. You just sounded really confident > that 5.x -> 6.0 won't work, so I hoped you also can tell why. > > I think we should try to be back-compat here, i.e. that a 6.0 (or 7.0) can > read a 5.0 (or 6.0) Solr. If ZK is our "format", then we should treat it as > a thing we want to support. That's just my opinion though. > > Shai > > On Tue, Feb 23, 2016 at 8:46 PM Anshum Gupta <ans...@anshumgupta.net> > wrote: > >> For that, we provide an index upgrade tool with 6.0, like we did in 5.0. >> >> On Tue, Feb 23, 2016 at 10:41 AM, Mike Drob <md...@apache.org> wrote: >> >>> A 5.x Solr could have indices that are still in a 4.x format, right? >>> That would be one point where it's not "fully back compatible." >>> >>> On Tue, Feb 23, 2016 at 12:27 PM, Shai Erera <ser...@gmail.com> wrote: >>> >>>> Wait, what do you mean by Lucene not supporting back-compat? Lucene 6.0 >>>> will be able to read Lucene 5.0 indexes. The only thing that we don't >>>> guarantee support for is API, which isn't the case here. >>>> >>>> So what's in 6.0 that can't read a 5.x Solr. It can't be the index >>>> format since that's supported by Lucene. Is it the ZK format? If so, should >>>> we try to "version" it so that a 6.0 code can read a 5.x version? Is it >>>> something else / additionally? >>>> >>>> Shai >>>> >>>> On Tue, Feb 23, 2016 at 7:06 PM Mark Miller <markrmil...@gmail.com> >>>> wrote: >>>> >>>>> Yes, we are allowed wide berth to break backcompat across major >>>>> versions and we cannot support rolling updates for the same reason Lucene >>>>> stopped trying to do full back compat across major versions. Without, we >>>>> can't properly innovate in the code or fix past mistakes and would also >>>>> burn lots of cycles we don't have on crazy, "sophisticated" back compat >>>>> layers. >>>>> >>>>> We don't even really support rolling updates between major versions. >>>>> We make a simple best effort. Until we have tests, it's going to be a >>>>> shaky >>>>> affair. There is a JIRA open now working on some testing I believe. >>>>> >>>>> - Mark >>>>> >>>>> On Tue, Feb 23, 2016 at 11:29 AM Shai Erera <ser...@gmail.com> wrote: >>>>> >>>>>> Hi >>>>>> >>>>>> I read in few emails/issue comments that rolling upgrades from 5.x to >>>>>> 6.0 isn't supported. Is it really the case? Does it mean that anyone who >>>>>> has a 5.x Solr cluster *must* incur down time when upgrading to 6.0? >>>>>> >>>>>> If this is really the case, can someone list the known issues/reasons >>>>>> for that?Can we do something about it, e.g. in a subsequent 5.6 release >>>>>> that will allow rolling upgrades (like the 5.4.1 fix that allowed rolling >>>>>> upgrades from pre-5.4 to 5.4)? >>>>>> >>>>>> I feel it's odd (and may not be taken well) if we force users to take >>>>>> down their entire cluster if they want to upgrade to 6.0. Definitely >>>>>> feels >>>>>> like it will also slow down 6.0 adoption. >>>>>> >>>>>> And if nothing can be done, what's the recommended way then to >>>>>> upgrade to 6.0? >>>>>> >>>>>> Shai >>>>>> >>>>> -- >>>>> - Mark >>>>> about.me/markrmiller >>>>> >>>> >>> >> >> >> -- >> Anshum Gupta >> > -- - Mark about.me/markrmiller
