A. Glossary
- cache
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An area for storing the data (pairs of keys and values) handled by EADS.
Up to 16 caches can be created in a cluster.
An EADS client manipulates data associated with a particular cache within a cluster.
- check for live servers
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This functionality detects a down EADS server in a cluster when it does not send heartbeats.
The check for live servers uses TCP.
- cluster
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A collection of multiple EADS servers. EADS clients recognize a cluster as a single storage destination.
A cluster consists of a set of EADS servers that share the same port numbers and the same multicast address within the same segment.
- disk cache
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A cache that uses a disk area to store data.
- EADS client
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A user program that connects to an EADS server by using client libraries provided by EADS.
- EADS server
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A server process that manages data consisting of keys and values.
- heartbeat
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A packet, delivered via multicast within a cluster, that indicates normal operation.
A heartbeat is sent using UDP.
- memory cache
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A cache that uses a memory area to store data.
- scale-out processing
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Processing that adds new EADS servers to a cluster without stopping the cluster.
- two-way cache
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A cache that uses a memory area and a disk area to store data.
- user function
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A program that defines a series of data operations (user processing) to be performed on a cache, such as data totaling and analysis.
User functions are created by the user and placed on an EADS server in advance. They are called and executed by the EADS client. The two methods for executing user functions are as follows:
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By specifying a key or a group
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By specifying an EADS server
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