update comments for partitioner and snitch
Project: http://git-wip-us.apache.org/repos/asf/cassandra/repo Commit: http://git-wip-us.apache.org/repos/asf/cassandra/commit/f8229c3f Tree: http://git-wip-us.apache.org/repos/asf/cassandra/tree/f8229c3f Diff: http://git-wip-us.apache.org/repos/asf/cassandra/diff/f8229c3f Branch: refs/heads/trunk Commit: f8229c3fb25c9f823939ac39558e5f29dd46ee3a Parents: 4f9d050 Author: Jonathan Ellis <jbel...@apache.org> Authored: Tue Mar 25 13:28:45 2014 -0500 Committer: Jonathan Ellis <jbel...@apache.org> Committed: Tue Mar 25 13:28:45 2014 -0500 ---------------------------------------------------------------------- conf/cassandra.yaml | 60 ++++++++++++++++++++---------------------------- 1 file changed, 25 insertions(+), 35 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/cassandra/blob/f8229c3f/conf/cassandra.yaml ---------------------------------------------------------------------- diff --git a/conf/cassandra.yaml b/conf/cassandra.yaml index d3c91ef..2edd498 100644 --- a/conf/cassandra.yaml +++ b/conf/cassandra.yaml @@ -78,27 +78,16 @@ authorizer: AllowAllAuthorizer # Will be disabled automatically for AllowAllAuthorizer. permissions_validity_in_ms: 2000 -# The partitioner is responsible for distributing rows (by key) across -# nodes in the cluster. Any IPartitioner may be used, including your -# own as long as it is on the classpath. Out of the box, Cassandra -# provides org.apache.cassandra.dht.{Murmur3Partitioner, RandomPartitioner -# ByteOrderedPartitioner, OrderPreservingPartitioner (deprecated)}. -# -# - RandomPartitioner distributes rows across the cluster evenly by md5. -# This is the default prior to 1.2 and is retained for compatibility. -# - Murmur3Partitioner is similar to RandomPartioner but uses Murmur3_128 -# Hash Function instead of md5. When in doubt, this is the best option. -# - ByteOrderedPartitioner orders rows lexically by key bytes. BOP allows -# scanning rows in key order, but the ordering can generate hot spots -# for sequential insertion workloads. -# - OrderPreservingPartitioner is an obsolete form of BOP, that stores -# - keys in a less-efficient format and only works with keys that are -# UTF8-encoded Strings. -# - CollatingOPP collates according to EN,US rules rather than lexical byte -# ordering. Use this as an example if you need custom collation. -# -# See http://wiki.apache.org/cassandra/Operations for more on -# partitioners and token selection. +# The partitioner is responsible for distributing groups of rows (by +# partition key) across nodes in the cluster. You should leave this +# alone for new clusters. The partitioner can NOT be changed without +# reloading all data, so when upgrading you should set this to the +# same partitioner you were already using. +# +# Besides Murmur3Partitioner, partitioners included for backwards +# compatibility include RandomPartitioner, ByteOrderedPartitioner, and +# OrderPreservingPartitioner. +# partitioner: org.apache.cassandra.dht.Murmur3Partitioner # Directories where Cassandra should store data on disk. Cassandra @@ -538,23 +527,18 @@ cross_node_timeout: false # # Out of the box, Cassandra provides # - SimpleSnitch: -# Treats Strategy order as proximity. This improves cache locality -# when disabling read repair, which can further improve throughput. -# Only appropriate for single-datacenter deployments. +# Treats Strategy order as proximity. This can improve cache +# locality when disabling read repair. Only appropriate for +# single-datacenter deployments. +# - GossipingPropertyFileSnitch +# This should be your go-to snitch for production use. The rack +# and datacenter for the local node are defined in +# cassandra-rackdc.properties and propagated to other nodes via +# gossip. If cassandra-topology.properties exists, it is used as a +# fallback, allowing migration from the PropertyFileSnitch. # - PropertyFileSnitch: # Proximity is determined by rack and data center, which are # explicitly configured in cassandra-topology.properties. -# - GossipingPropertyFileSnitch -# The rack and datacenter for the local node are defined in -# cassandra-rackdc.properties and propagated to other nodes via gossip. If -# cassandra-topology.properties exists, it is used as a fallback, allowing -# migration from the PropertyFileSnitch. -# - RackInferringSnitch: -# Proximity is determined by rack and data center, which are -# assumed to correspond to the 3rd and 2nd octet of each node's -# IP address, respectively. Unless this happens to match your -# deployment conventions (as it did Facebook's), this is best used -# as an example of writing a custom Snitch class. # - Ec2Snitch: # Appropriate for EC2 deployments in a single Region. Loads Region # and Availability Zone information from the EC2 API. The Region is @@ -568,6 +552,12 @@ cross_node_timeout: false # ssl_storage_port on the public IP firewall. (For intra-Region # traffic, Cassandra will switch to the private IP after # establishing a connection.) +# - RackInferringSnitch: +# Proximity is determined by rack and data center, which are +# assumed to correspond to the 3rd and 2nd octet of each node's IP +# address, respectively. Unless this happens to match your +# deployment conventions, this is best used as an example of +# writing a custom Snitch class and is provided in that spirit. # # You can use a custom Snitch by setting this to the full class name # of the snitch, which will be assumed to be on your classpath.
