Buckets are used to compartmentalize data within Couchbase Server and are also used as the basic mechanism used to replicate and duplicate information (if supported). Couchbase Server supports two different bucket types. These are:
The memcached buckets are designed to fully support the core memcached protocol as an in-memory caching solution. The support and functionality is therefore limited to the same functionality as within a standalone memcached implementation.
The main features are:
Item size is limited to 1 Mbyte.
Persistence is not supported.
Replication is not supported; data is available only on one node.
Statistics are limited to those directly related to the in-memory nature of the data. Statistics related to persistence, disk I/O and replication/rebalancing are not available.
Client setup should use ketama consistent hashing
memcached buckets do not use vBuckets, so there is no rebalancing.
Couchbase buckets support the full range of Couchbase-specific functionality, including balancing, persistence and replication. The main features are:
Item size is limited to 20 Mbyte.
Persistence, including data sets larger than the allocated memory size.
Replication and rebalancing are fully supported.
Full suite of statistics supported.
In addition to these overall bucket differences, there are also security and network port differences that enable you to configure and structure the connectivity to the different bucket types differently.
There are three bucket interface types that can be be configured:
The default Bucket
The default bucket is a Couchbase bucket that always resides on port 11211 and is a non-SASL authenticating bucket. When Couchbase Server is first installed this bucket is automatically set up during installation. This bucket may be removed after installation and may also be re-added later, but when re-adding a bucket named "default", the bucket must be place on port 11211 and must be a non-SASL authenticating bucket. A bucket not named default may not reside on port 11211 if it is a non-SASL bucket. The default bucket may be reached with a vBucket aware smart client, an ASCII client or a binary client that doesn't use SASL authentication.
Non-SASL buckets may be placed on any available port with the exception of port 11211 if the bucket is not named "default". Only one Non-SASL bucket may placed on any individual port. These buckets may be reached with a vBucket aware smart client, an ASCII client or a binary client that doesn't use SASL authentication
SASL authenticating Couchbase buckets may only be placed on port 11211 and each bucket is differentiated by its name and password. SASL bucket may not be placed on any other port beside 11211. These buckets can be reached with either a vBucket aware smart client or a binary client that has SASL support. These buckets cannot be reached with ASCII clients.