What are our expectations regards compatibility between hbase1 and hbase2? Lets have a chat about it. Here are some goal posts.
+ You have to upgrade to hbase-1.x before you can migrate to hbase-2. No migration from < hbase-1 (Is this too onerous? Should we support 0.98 => 2.0?). + You do NOT have to upgrade to the latest release of hbase1 to migrate to hbase2; being up on hbase-1.0.0+ will be sufficient. + You'll have to update your hbase1 coprocessors to deploy them on hbase2. A bunch of CP API has/will change by the time hbase2 comes out; e.g. watching for region split on RegionServer no longer makes sense given Master runs all splits now. + An hbase1 client can run against an hbase2 cluster but it will only be able to do DML (Get/Put/Scan, etc.). We do not allow being able to do admin ops using an hbase1 Admin client against an hbase2 cluster. We have some egregious API violations in branch-1; e.g. we have protobuf in our API (See HBASE-15607). The notion is that we can't afford a deprecation cycle purging this stuff from our Admin API. What you all think? St.Ack
