We replicate via
both Solr and HDFS.
just one has huge
We are working on
A new per collection
When a replica goes
down, it is replaced on
a node that is still up.
A shared filesystem as
well means all replicas
can go down and you
can still automatically
How Does it Work?
SolrCloud elects a fault tolerant,
single node to be an Overseer.
The Overseer monitors the cluster
state in ZooKeeper.
Creates a new SolrCore on a machine
that is up when necessary to replace
We did a straw man implementation
of SolrCloud first.
We did the same for tests.
We favored integration tests over
We did not make enough tests.
For a variety of reasons.
The Lucene / Solr testing
framework hurts in order to help.
The Lucene / Solr
The Jenkins Cluster.
We avoided doing them early - too
They can be dangerous to future
contributors / refactoring.
Some of the early mocking that did get
in is a little painful.
We need them for good unit tests.
Lucene has A+ testing culture. In
many cases, it’s easier for Lucene.
Solr has a C testing culture.
Solr needs to get better.
More focus on back filling tests
when adding features or changing
More focus on fixing frequently
More focus on unit tests.