HFile v3 is probably a good example. An appendix entry that has details that would be relevant if debugging or troublehsooting.
And a note for the upgrade section about it being in place by default and how an operator would avoid that if they need to for some reason (like an esoteric Hadoop FS or just conservative ops position). I've seen conflicting statements already about the impact on durability, for example, and we should be proactive in setting expectations since folks will be concerned as soon as they hear we have our own DFS client. On Wed, Mar 28, 2018, 01:49 张铎(Duo Zhang) <palomino...@gmail.com> wrote: > Any examples which we could follow? This is not a user visible feature, so > not sure what is the best way to mention it in the ref guide. > > 2018-03-27 23:47 GMT+08:00 Sean Busbey <bus...@apache.org>: > > > Could y'all get some of this into the reference guide? Talks and > > release notes are great, but I really want us to make sure operators > > have a nice place to figure out all the stuff we're landing in 2.0. > > > > On Tue, Mar 27, 2018 at 10:13 AM, Yu Li <car...@gmail.com> wrote: > > > @Mike > > > FWIW, besides checking the JIRAs and codes, the talk Duo gave in our > > > HBaseCon 2016 may help you better understand the whole picture, please > > > check page 14 to 20 of this presentation > > > <https://www.slideshare.net/HBaseCon/apache-hbase- > > improvements-and-practices-at-xiaomi> > > > on > > > slideshare. > > > > > > Best Regards, > > > Yu > > > > > > On 27 March 2018 at 14:26, 张铎(Duo Zhang) <palomino...@gmail.com> > wrote: > > > > > >> 2018-03-27 12:35 GMT+08:00 Mike Drob <md...@apache.org>: > > >> > > >> > Hi folks, > > >> > > > >> > I've been working on some of the docs relating to the upcoming 2.0 > > >> release > > >> > and have struggled to find content around AsyncWAL. My impression is > > that > > >> > this is a pretty important new feature, yet there's nothing in the > ref > > >> > guide about it. > > >> > > > >> > Does it have a different name that I'm not familiar with? > > >> > > > >> > If it's not in the ref guide, should I file a JIRA issue for > somebody > > to > > >> > generate that content? Specific things that I'd be looking for are: > > >> > - How to enable/disable > > >> > > > >> See HBASE-15536, just like the old way, config hbase.wal.provider > > >> > > >> > - How does this impact data durability, MTTR, failover scenarios, > etc. > > >> > > > >> Does not impact these things. > > >> > > >> > - How does this impact replication > > >> > > > >> Ditto. > > >> > > >> > - Which configuration knobs exist and when would I want to tune them > > >> > > > >> Usually you do not need to tune anything... > > >> Before committing HBASE-15536 we have done a lot of performance > > testings. > > >> There are two configs which may effect performance, one > > >> is hbase.wal.batch.size, and the other > > >> is hbase.wal.async.use-shared-event-loop. But it is hard to say how to > > >> tune > > >> them... > > >> And another thing is that, with AsyncFSWAL we can set a lower timeout > > when > > >> writing WAL, but now it just shares the common dfs configuration. > Maybe > > we > > >> should file an issue for it. > > >> > > >> > > > >> > As a last resort, I can try to dig through RNs in existing issues, > but > > >> > that's been pretty hit or miss (mostly miss) for me so far too. > > >> > > > >> > I think at least we need to mention the reason why we introduce > > >> AsyncFSWAL > > >> and make it default for 2.0 in our refguide. > > >> > > >> > Thanks, > > >> > Mike > > >> > > > >> > > >
