Upgrading Cassandra: 0.7.1 to 0.8.x¶

Upgrading from version 0.7.1 or later can be done with a rolling restart, one node at a time. You do not need to bring down the whole cluster at once.

If you are running version 0.7.0, first upgrade to 0.7.1 and then perform the upgrade to 0.8.

To upgrade a binary package installation from 0.7.1 to 0.8.x:

On each node, download and unpack the 0.8 installation package from the downloads section of the Cassandra website.
Account for New and Changed Parameters in cassandra.yaml. You can copy your existing 0.7.x configuration file into the upgraded Cassandra instance and manually update it with new content.
Make sure any client drivers – such as Hector or Pycassa clients – are 0.8-compatible.
Run nodetool drain on the 0.7.x node to flush the commit log.
Restart the Cassandra node, monitoring the log files for any issues.
After upgrading and restarting all Cassandra nodes, restart client applications.

To upgrade a CentOS/RHEL packaged release installation from 0.7.1 to 0.8.x:

On each of your Cassandra nodes, run sudo yum install apache-cassandra08.
Account for New and Changed Parameters in cassandra.yaml. The installer creates the file cassandra.yaml.rpmnew in /etc/cassandra/default.conf/. You can diff this file with your existing configuration and add new content.
Make sure any client drivers – such as Hector or Pycassa clients – are 0.8-compatible.
Run nodetool drain on the 0.7.x node to flush the commit log.
Restart each Cassandra node, one at a time, monitoring the log files for any issues.
After upgrading and restarting all Cassandra nodes, restart client applications.

To upgrade a Debian/Ubuntu packaged release installation from 0.7.1 to 0.8.x:

On each of your Cassandra nodes, run sudo apt-get install cassandra08.
Account for New and Changed Parameters in cassandra.yaml. The installer creates the file cassandra.yaml.rpmnew in /etc/cassandra/default.conf/. You can diff this file with your existing configuration and add new content.
Make sure any client drivers – such as Hector or Pycassa clients – are 0.8-compatible.
Run nodetool drain on the 0.7.x node to flush the commit log.
Restart each Cassandra node, one at a time, monitoring the log files for any issues.
After upgrading and restarting all Cassandra nodes, restart client applications.

New and Changed Features¶

By default, JMX now listens on port 7199. Prior to 0.8 the default JMX port was 8080.
Avro record classes used in map/reduce and Hadoop streaming code have moved from org.apache.cassandra.avro to org.apache.cassandra.hadoop.avro, so applications using these classes will need to be updated accordingly.
The loadbalance command has been removed from nodetool. For similar behavior, decommission then rebootstrap with empty initial_token.
New CQL client API and JDBC/DBAPI2-compliant drivers for Java and Python, respectively. See Getting Started with CQL.
New distributed Counters feature; see the Cassandra Wiki.
New optional intranode encryption. See internode_encryption.
New compaction multithreading and rate-limiting; see compaction_multithreading and compaction_throughput_mb_per_sec in cassandra.yaml.
Previous to 0.8, sstable2json would write column names and values as hex strings, and now creates human readable values based on the comparator/validator. As a result, JSON dumps created with older versions of sstable2json are no longer compatible with json2sstable, and imports must be made with a configuration that is identical to the export.

New and Changed Parameters¶

This table lists cassandra.yaml parameters that have changed between 0.7.0 and 0.8. See the cassandra.yaml reference for details on these parameters.

Option	Default Value
0.8 Release
seed_provider	SimpleSeedProvider
seeds	Note: now a comma-delimited list in double quotes.
memtable_total_space_in_mb	1/3 of heap
compaction_throughput_mb_per_sec	16
concurrent_compactors	One per CPU
internode_encryption	none
keystore	conf/.keystore
keystore_password	cassandra
truststore	conf/.truststore
truststore_password	cassandra
0.7.5 Release
memtable_flush_queue_size	4
disk_access_mode	Omitted from default config file - used for debugging only
0.7.4 Release
rpc_min_threads	16
rpc_max_threads	Unlimited
incremental_backups	false
Keyspace definition	Removed
0.7.3 Release
hinted_handoff_throttle_delay_in_ms	50
compaction_preheat_key_cache	true
0.7.0. > 0.7.2 Release
max_hint_window_in_ms	3600000 (One hour)
flush_largest_memtables_at	0.75
reduce_cache_sizes_at	0.85
reduce_cache_capacity_to	0.6
concurrent_reads	32

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