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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "Hbase/HBaseVersions" by ToddLipcon
Date Thu, 24 Jun 2010 03:25:54 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for change notification.

The "Hbase/HBaseVersions" page has been changed by ToddLipcon.


New page:
= HBase Versions =

There are currently two active branches of HBase:
 * '''0.20''' - the current stable release series, being maintained with patches for bug fixes
only. This release series does '''not''' support HDFS durability - edits may be lost in the
case of node failure.
 * '''0.89''' - a development release series with active feature and stability development,
not currently recommended for production use. This release '''does''' support HDFS durability
- cases in which edits are lost are considered serious bugs.

== 0.20 Series ==

The 0.20 series was first released in fall of 2009. It is in use in production in a number
of deployments. Development of new features and improvements is largely halted on this release
series, though it will continue to have bug fixes applied, so long as the bug fixes do not
have high risk of regressions.

== 0.89 "Development" Series ==

The 0.89 series is a departure from the previous sequential (0.18, 0.19, 0.20) versioning.
Here is a short FAQ describing the version numbering and purpose of this series:

=== Why skip from 0.20 to 0.89? ===

The last few releases of HBase have been in lockstep with Hadoop releases (eg hbase 0.X.*
would work with Hadoop 0.X.*). However, Hadoop's release process has slowed down, and we have
the desire to release HBase on a different timeline from Hadoop, with each HBase release potentially
being compatible with multiple versions of Hadoop. To signify this departure from lockstep
releases, and since we intend for the next release of HBase to continue to support Hadoop
0.20, we don't want to call the next release 0.21.

There's also a general sentiment that, feature-wise, HBase is nearing a 1.0 level. The project
has implemented the majority of the features described in the Bigtable paper plus many more.
It's also starting to take a more central role in the production infrastructures of many companies.
So, we'd really like to do a 1.0 release some time in the coming year (no dates, but maybe
early 2011?) However, we're not at 1.0 yet. There are still stability bugs to iron out, and
some features in progress that we'd like to have done for 1.0.

So, given that, the next stable release will be called HBase 0.90. This indicates (a) a big
step up from 0.20, (b) we are nearing 1.0, and (c) we are not tied to Hadoop version numbering.

We're not ready to release 0.90 yet - there are a lot of blockers still open affecting reliability
and stability, and we haven't done extensive testing of trunk under production workloads.
But, the development community feels there's a lot of stuff in trunk that's worth showing
to the user community. To that end, we are releasing a series of development builds cut from
trunk leading up to the 0.90 release. This release series is going to be called 0.89.

Users familiar with Linux kernel development from several years back will recall that Linux
2.3.* was a development series leading up to Linux 2.4, and Linux 2.5 led up to Linux 2.6.
We have not decided to go with a strict odd/even for HBase for all future releases, but this
particular release is similar to that process.

=== What will version numbers look like in the 0.89 series? ===

This development series will have version numbers 0.89.YYYYMMDD, the last segment of the version
number indicating the date on which the release was branched from trunk. These releases won't
have followup patch releases, and will only go through basic cluster testing, but provide
usable snapshots of trunk development so that the community can begin to work with the new
code and provide early feedback based on their use cases and testing. We're confident this
will help make 0.90 the most stable release yet.

If there is a bug found in a release 0.89.YYYYMMDD, we will '''not''' release 0.89.YYYYMMDD.1.
All releases in this series will be new branches from trunk. This is to ensure that we are
making forward progress towards our larger goals for 0.90, and to reduce maintenance burden
on the development team.

=== What releases have been made on the 0.89 series? ===

The first release in the 0.89 series will be 0.89.20100621, due to be released the week of

=== Are the 0.89 releases official releases? ===

Yes, these releases have been voted on by the HBase development team, and considered official
releases with regard to license policies, etc. The two main differences between this release
series and a stable series are (a) no followup bugfix releases to any individual release,
and (b) a lower bar for spit and polish, testing, etc.

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