Simple Mapping¶

dovecot.conf:

dict {
 cassandra = cassandra:/etc/dovecot/dovecot-dict-cql.conf.ext
}

dovecot-dict-cql.conf.ext:

# Location of Cassandra Server(s)
# ALL local Cassandra nodes should be added; the Cassandra driver code uses this list internally to find the initial list of Cassandra nodes.
# Cassandra will perform load balancing internally among all the local Cassandra nodes (including ones not specified here).
connect = host=10.2.3.4 \
host=10.3.4.5 \
host=10.4.5.6 \
keyspace=mails \

# Cassandra connection port
# port=9042 \


# User/password authentication
# user=cassandra_user \
# password=cassandra_pass \


# If this error is seen: "Host x.x.x.x received invalid protocol response Invalid or unsupported protocol version: 4"
# Add this parameter to force Cassandra protocol downgrade to version 3
# version=3 \

# For multi-DC consistency on normal operation (see below), add:
# write_consistency=each-quorum \
# write_fallback_consistency=local-quorum \
# delete_consistency=each-quorum \
# delete_fallback_consistency=local-quorum \

# (v2.2.24+) Connection/Request timeouts
# connect_timeout=5 \
# request_timeout=5 \

# (v2.2.24+) Define the number of Cassandra access threads to use
# num_threads=4 \

# (v2.2.26+) Use latency-aware routing
# See: http://datastax.github.io/cpp-driver/topics/configuration/#latency-aware-routing
# latency_aware_routing=y \

# DEBUG: (v2.2.25+) Warning timeouts; if request takes longer than this amount of seconds, log query at WARN level
# warn_timeout=5 \

# (v2.2.27.2+) Interval between heartbeats to Cassandra server
# heartbeat_interval=30s \


# (v2.2.27.2+) If heartbeat hasn't been received for this long, reconnect to Cassandra.
# idle_timeout=1min \

# (v2.2.28+) Automatically retry Cassandra queries. By default
# nothing is currently retried, so these settings should be enabled.
# how many times and in which intervals the execution is retried on top of the original request sent
execution_retry_interval=500ms \
execution_retry_times=3 \

# (v2.2.32+) Cassandra query result paging:  Add page_size=n to dovecot-dict-cql.conf.ext's connect setting.
# can also add log_level=debug so it logs about each pageful.
# page_size=500 \

# DEBUG: Set log level
# log_level=2 \


# DEBUG: Output all Cassandra queries to log at DEBUG level
# debug_queries=y \

# DEBUG: Output internal metrics in JSON format to this file.
# Format of data can be found at the end of this document.
# metrics=/tmp/dovecot-cassandra.metrics.%{pid}

Append dict mappings to the resulting dovecot-dict-cql.conf.ext as described in 4.3.2.4.1 SWIFT dict map or 4.3.2.1.1 Scality sproxyd dict map.

Cassandra Keyspace

The Cassandra keyspace is created/initialized with the following CQL commands:

create keyspace if not exists mails
WITH REPLICATION = {
'class':'SimpleStrategy',
'replication_factor':3 };
use mails;
drop table user_index_objects;
drop table user_mailbox_index_objects;
drop table user_mailbox_objects;
drop table user_mailbox_buckets;
drop table user_fts_objects;
drop table user_index_diff_objects;
drop table user_mailbox_index_diff_objects;
drop table user_mailbox_objects_reverse;

SWIFT / S3 Table Creation

use mails;
create table user_index_objects (u text, n text, i text, primary key (u, n));
create table user_mailbox_index_objects (u text, g blob, n text, i text, primary key ((u, g), n));
create table user_mailbox_objects (u text, g blob, b int, n blob, i text, primary key ((u, g, b), n));
create table user_mailbox_buckets (u text, g blob, b int, primary key ((u, g)));
create table user_fts_objects (u text, n text, i text, primary key (u, n));
create table user_index_diff_objects (u text, h text, m text, primary key (u, h));
create table user_mailbox_index_diff_objects (u text, g blob, h text, m text, primary key (u, g, h));
create table user_mailbox_objects_reverse (u text, g blob, n blob, i text, primary key (i, n));

Scality sproxyd Table Creation

use mails;
create table if not exists user_index_objects (u text,n text,i blob,primary key (u, n));
create table if not exists user_mailbox_index_objects (u text,g blob,n text,i blob,primary key ((u, g), n));
create table if not exists user_mailbox_objects (u text,g blob,b int,n blob,i blob,primary key ((u, g, b), n));
create table if not exists user_mailbox_buckets (u text,g blob,b int,primary key ((u, g)));
create table if not exists user_fts_objects (u text,n text,i blob,primary key (u, n));
create table if not exists user_index_diff_objects (u text,h text,m text,primary key (u, h));
create table if not exists user_mailbox_index_diff_objects (u text,g blob,h text,m text,primary key (u, g, h));
 create table if not exists user_mailbox_objects_reverse (u text,g blob,n blob,i blob,primary key (i, n));

The following base tables are always needed:

user_index_objects

user_mailbox_index_objects

user_mailbox_objects

user_mailbox_buckets

user_fts_objects

These use the username as the partition key, which means that data distribution across Cassandra nodes are done per-user. As long as there are a lot of users this should work fine. Additionally, each user’s entire data must fit into a single Cassandra node, but since the amount of data is quite small this isn’t a practical problem.

Simple Mapping¶

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