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Mirrors

Describes mirrors the instance is a member of.

Synopsis

[Mirrors]    Name=GUID,2,1,Defined Primary,QOSTimeout,0,UseSSL,VirtualAddress,0,AgentAddress,AgentPort,ArbiterNode, AllowParallelDejournaling

Description

Each entry consists of comma-separated values that define a mirror. From left to right:

  • Name – Required. Unique name by which you can identify this mirror. An uppercase alphanumeric string with a maximum length of 15 characters.

  • GUID – Required. An internal GUID, unique to this mirror.

  • 2 – For internal use.

  • 1 – For internal use.

  • Defined Primary – Used to disable mirror failover, generally for maintanance purposes. Manipulated via the nofailover option when shutting down Caché or the ^MIRROR routine. This contains the mirror name of the member which must be the primary. It is cleared automatically when that node starts up and becomes the primary.

  • QOSTimeout – Quality of Service Timeout: the maximum time, in milliseconds, that a failover member waits for a response from the other failover member before taking action; also applies to the arbiter’s wait for a failover member’s response. The default is 8000ms; typically, deployments on physical (non-virtualized) hosts with a dedicated local network can reduce this setting if a faster response to outages is required. See Configuring the Quality of Service (QoS) Timeout Setting in the “Mirroring” chapter of the Caché High Availability Guide for more information on the QoS Timeout setting.

  • 0 – For internal use.

  • UseSSL – To provide security within a mirror, you can configure its nodes to use SSL/TLS. This provides for both authentication of one node to another, and for encrypted communication between nodes. To use SSL/TLS with a mirror, each member (failover or async) uses a pair of SSL/TLS configurations, %Mirror_Client and %Mirror_Server. These configurations must already exist on each member when SSL/TLS is enabled for the mirror. Instructions for setting up SSL are in the section Creating and Editing SSL/TLS Configurations for a Mirror of the “Using SSL/TLS with Caché” chapter of the Caché System Security Guide. Values are 0 (no, default) or 1 (yes).

  • VirtualAddress – Specifies a virtual IP address. You can configure a mirror virtual IP address (VIP) so that all external clients (language bindings, ODBC/JDBC/SQL clients, direct-connect users, and so on) connect to the mirror through a single address. This virtual IP address is automatically bound to an interface on the current primary member. To use a VIP, which requires that both failover members be on the same subnet. For more information, see the Configuring a Mirror Virtual IP (VIP) section of the chapter “Mirroring” in the Cache High Availability Guide.

  • 0 – For internal use.

  • ArbiterNode – The network address of the arbiter configured for this mirror. The arbiter is an independent system hosting an ISCAgent with which the failover members of a mirror maintain continuous contact, providing them with the context needed to safely make failover decisions when they cannot communicate directly. .

  • ArbiterPort – The port used by the configured arbiter’s ISCAgent process (2188 by default).

  • FailoverCompressionMode – Determines whether journal data is compressed before being transmitted from the primary to the backup. Values are 0 (System Selected, which optimizes for response time between failover members), 1 (Uncompressed) and 2 (Compressed).

  • AsyncCompressionMode – Determines whether journal data is compressed before being transmitted from the primary to async members. Values are 0 (System Selected, which optimizes for network utilization), 1 (Uncompressed) and 2 (Compressed).

  • AllowParallelDejournaling – Determines which type of mirror members can run parallel dejournaling updaters. Possible values are 0 (failover and disaster recovery members), 1 (failover members only), and 2 (all members).

Examples

Each entry is on one line:

MIMI=C7BA9224-3851-47D4-83BD-0C01AEEACC76,2,1,,2000,0,0,,0,arbhost|2188,0,0
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Management Portal

On the page System Administration > Configuration > Mirror Settings > Create a Mirror> Join as Failover (or Join as Async), enter the requested information.