Hello,

after many years of interleaved intense efforts and no care at all (in
order to focus to other features), the first stable version of Redis
with native support for clustering is out.
I see this more like a beginning of a new stage, than the termination
of an old one. Here we are giving the foundations to make it simpler
for people to work with Redis in larger environments.
What Redis 3.0.0 is providing today, will likely take 1 or 2 years to
mature, with our community that can build an experience on what we
got, and get some feeling about what we should aim for the future.

Redis 3.0.0 contains many more features, but the list does not provide
justice to the work this release received, since an impressive number
of things were backported into 2.8 in the course of the releases in
order to provide them to the users ASAP, because I was conscious of
the fact 3.0.0 was special, and it needed much more time before to
reach stability. Now that we returned, hopefully, into a normal
workflow, new features are no longer backported into stable releases.
Redis 3.0.0 is actually the first example of this new development
model: there are already interesting new things into the "unstable"
branch that I avoided putting into the mix of 3.0.0.

The cluster specification was updated for the release. You may want to
read it again if you are interested in Redis Cluster:
http://redis.io/topics/cluster-spec
We also have a new section with Cluster commands in the redis.io web
site: http://redis.io/commands#cluster

Other new things implemented in 3.0.0 that may be significative to
users not interested in Redis Cluster are:

* An improved LRU algorithm, ways more precise to evict the older keys.
* Redis 3.0.0 is generally sensibly faster under high (pipelined) load.
* AOF rewrite was reworked in order to reduce latency spikes with slow
disks when the process undertakes the final "write" of the accumulated
buffer.

Here is the full changelog:
https://raw.githubusercontent.com/antirez/redis/3.0/00-RELEASENOTES

Before closing the line, just a few more words. I believe that Redis
Cluster will be a major thing in the Redis ecosystem. Maybe it works
great from day one, maybe it will need a few more iterations, and
possibly with 3.2 we'll improve support for many stuff, but my guess
is that Redis 3.0.0 today, in some way, changes what Redis is. Redis
used to be this little cute instance you run to solve certain
problems. Later we evolved it into something more, with Sentinel there
is an HA story to tell, and it is possible to use Redis for more
complex tasks. Now with Redis Cluster the attempt is to give users the
step forward, a system that out of the box is capable of a certain
degree of automatic scalability and fault tolerance, a degree that
should be enough for many users to change their view of Redis as a
tool, and as the possible applications it is suitable for.

I'm happy about the journey that started when I realized Redis was
limited by its single instance nature, and today ends with this first
stable release of Redis Cluster. I would do it again, and I really
hope you'll have fun with Redis 3.0.0, the kind of fun we code
addicted have from time to time while trying to make shit done.

Salvatore

--
Salvatore 'antirez' Sanfilippo
open source developer - Pivotal http://pivotal.io

"If a system is to have conceptual integrity, someone must control the
concepts."
       — Fred Brooks, "The Mythical Man-Month", 1975.