You can upgrade from these releases to DataStax Enterprise 3.0.x:
You can upgrade to DataStax Enterprise 3.0 from a version of DataStax Community or Cassandra that is earlier, but not later, than the one included in DataStax Enterprise 3.0.x. See the release notes for version information.
Upgrade one data center at a time.
To start the upgrade process, perform the pre-upgrade steps, and then follow the link in step 4 for the particular version you are upgrading.
During an upgrade, limit activity on the node:
Make a backup of the data by taking a snapshot of the node to be upgraded.
Run nodetool drain to flush the commit log of the old installation:
nodetool drain –h <hostname>
If you are upgrading a DSE Search/Solr node, this step is mandatory. This step is highly recommended for upgrading other nodes because, in the event of a power failure during the upgrade, data loss could occur.
On Debian/Ubuntu, save the cassandra.yaml (and cassandra-topology.properties file if you use the PropertyFileSnitch) from the old installation in a safe location.
On RHEL-based platforms, RPM saves the file automatically during the upgrade process instead of overwriting it. RPM output looks something like this:
warning: /etc/cassandra/default.conf/cassandra.yaml saved as /etc/cassandra/default.conf/cassandra.yaml.rpmsave
On tarball platforms, you install the new release in a different location, so the old files are not overwritten.
Regardless of the platform, if you customized any other files, copy the files from the old installation to a safe location before performing an in-place upgrade that overwrites customized files.
Upgrade your installation according to these instructions:
Observe the following order for upgrading nodes in a mixed workload cluster:
DSE Search/Solr nodes are upgraded last because they are more sensitive to schema disagreements.
The versions of components that changed for each DataStax release are listed in the Release notes for that version. The cassandra.yaml file included in DSE 3.0.x contains security options that are not included in the Apache Cassandra 1.1.9 file.
For a complete list of Cassandra changes and new features, see:
Upgrading SSTables is highly recommended under these conditions:
Upgrade SSTables before doing these operations:
Because these operations copy SSTables within the cluster and the on-disk format sometimes changes between major versions, upgrade SSTables now to prevent possible SSTable incompatibilities. Follow upgrade procedures in this document to upgrade SSTables at the end of the process.
Between the time the first node in a cluster begins the upgrade process until the last node completes the process, a schema disagreement condition exists. Cassandra throws a SchemaDisagreementException when a schema disagreement occurs. This is expected behavior. Upgrade procedures include steps for resolving schema disagreements.
When the schema disagreement exists, client interfaces block the following operations:
DDL, TRUNCATE, and Solr queries are not supported during a rolling restart. For example, during a rolling restart, these are the CQL commands that are and are not supported:
|OK to Run||Do Not Run||Do Not Run (continued)|
|DELETE||ALTER TABLE||DROP TABLE|
|INSERT||CREATE TABLE||DROP INDEX|
|SELECT||CREATE INDEX||DROP KEYSPACE|
Exception: After upgrading from DataStax Enterprise 2.1.x or earlier, Solr queries are not supported until all nodes are upgraded and schema disagreements are resolved.
NEWS.txt contains late-breaking information about upgrading from previous versions of Cassandra.
A NEWS.txt or a NEWS.txt archive is installed in the following locations:
NEWS.txt is also posted on the Apache Cassandra project web site.
Unpack NEWS.txt.gz if it is an archive. For example:
cd /usr/share/doc/dse-libcassandra-3.0. sudo gunzip NEWS.txt.gz
Take at look at the information that is pertinent to your old version if there is any. For example, if you upgrade from some early versions, it might be necessary to upgrade SSTables.