12. Glossary¶
- GC
Abbreviation for garbage collection
- Java heap
Area in which the Java VM allocates memory according to a memory acquisition request from a Java application. Target of GC
- Java memory pool
Memory area prepared by the Java VM for Java applications
- JMX
Abbreviation for Java Management Extensions. Specification used for Java that manages and monitors the hardware and software in the network
- JVM operation log
File for recording JVM monitor resource operation information. The file is created in the following location:
<EXPRESSCLUSTER_install_path>/log/ha/jra/ jragent*.log
(* indicates a number starting at 0.)
- JVM statistics log
File for recording statistics obtained from JVM monitor resource. The file is created in the following location:
<EXPRESSCLUSTER_install_path>/log/ha/jra/*.stat
- Interconnect
A dedicated communication path for server-to-server communication in a cluster.
(Related terms: Private LAN, Public LAN)
- Virtual IP address
IP address used to configure a remote cluster.
- Management client
Any machine that uses the Cluster WebUI to access and manage a cluster system.
- Startup attribute
A failover group attribute that determines whether a failover group should be started up automatically or manually when a cluster is started.
A disk that multiple servers can access.
A cluster system that uses one or more shared disks.
- Switchable partition
A disk partition connected to multiple computers and is switchable among computers.
(Related terms: Disk heartbeat partition)
- Cluster system
Multiple computers are connected via a LAN (or other network) and behave as if it were a single system.
- Cluster shutdown
To shut down an entire cluster system (all servers that configure a cluster system).
- Cluster partition
A partition on a mirror disk or a hybrid disk. Used for managing mirror disks or hybrid disks.
(Related term: Disk heartbeat partition)
- Active server
A server that is running for an application set.
(Related term: Standby server)
- Secondary server
A destination server where a failover group fails over to during normal operations.
(Related term: Primary server)
- Standby server
A server that is not an active server.
(Related term: Active server)
- Disk heartbeat partition
A partition used for heartbeat communication in a shared disk type cluster.
- Data partition
A local disk that can be used as a shared disk for switchable partition. Data partition for mirror disks or hybrid disks.
(Related term: Cluster partition)
- Network partition
All heartbeat is lost and the network between servers is partitioned.
(Related terms: Interconnect, Heartbeat)
- Node
A server that is part of a cluster in a cluster system. In networking terminology, it refers to devices, including computers and routers, that can transmit, receive, or process signals.
- Heartbeat
Signals that servers in a cluster send to each other to detect a failure in a cluster.
(Related terms: Interconnect, Network partition)
- Public LAN
A communication channel between clients and servers.
(Related terms: Interconnect, Private LAN)
- Failover
The process of a standby server taking over the group of resources that the active server previously was handling due to error detection.
- Failback
A process of returning an application back to an active server after an application fails over to another server.
- Failover group
A group of cluster resources and attributes required to execute an application.
- Moving failover group
Moving an application from an active server to a standby server by a user.
- Failover policy
A priority list of servers that a group can fail over to.
- Private LAN
LAN in which only servers configured in a clustered system are connected.
(Related terms: Interconnect, Public LAN)
- Primary (server)
A server that is the main server for a failover group.
(Related term: Secondary server)
- Floating IP address
Clients can transparently switch one server from another when a failover occurs.
Any unassigned IP address that has the same network address that a cluster server belongs to can be used as a floating address.
- Master server
Server displayed on top of the Master Server in Server Common Properties in the Cluster WebUI
- Mirror disk connect
LAN used for data mirroring in mirror disk or hybrid disk. Mirror connect can be used with primary interconnect.
- Mirror disk type cluster
A cluster system that does not use a shared disk. Local disks of the servers are mirrored.