startrcrelationship

The startrcrelationship command starts the Metro Mirror or Global Mirror relationship copy process, sets the direction of copy if undefined, and optionally, marks the secondary VDisk of the relationship as clean. The relationship must be a stand-alone relationship.

Syntax


>>- svctask -- -- startrcrelationship -- ----------------------->

>--+--------------------------+-- --+----------+-- ------------->
   '- -primary --+- master -+-'     '- -force -'      
                 '- aux ----'                         

>--+----------+-- --+- rc_rel_id ---+--------------------------><
   '- -clean -'     '- rc_rel_name -'

Parameters

-primary master | aux: (Optional) Specifies the copy direction by defining whether the master or auxiliary disk becomes the primary (source). This parameter is required when the primary is undefined if, for example, the relationship is in the idling state.
-force: (Optional) Specifies that you want the system to process the copy operation even if it might lead to a temporary loss of consistency while synchronization occurs. This parameter is required if the relationship is in the Consistentstopped state, but is not synchronized or in the Idling state, but is not synchronized.
-clean: (Optional) Specifies that the VDisk that is to become a secondary is clean; any changes made on the secondary VDisk are ignored, and only changes made on the clean primary VDisk are considered when synchronizing the primary and secondary disks. The relationship must be in an Idling (connected) state for this parameter to work.
Attention: This flag should only be used when the primary and secondary VDisks contain identical data. Otherwise, relationships that are not consistent are reported as consistent. Once this has been done there is no method to determine whether these VDisks ever reach a true consistent state until a full background copy can be carried out again.
rc_rel_id | rc_rel_name: (Required) Specifies the ID or name of the relationship that you want to start in a stand-alone relationship.

Description

The startrcrelationship command starts a stand-alone relationship. The command fails if it is used to start a relationship that is part of a consistency group.

This command can only be issued to a relationship that is connected. For a relationship that is idling, this command assigns a copy direction (primary and secondary roles) and begins the copy process. Otherwise, this command restarts a previous copy process that was stopped either by a stop command or by some I/O error.

If the resumption of the copy process leads to a period of time when the relationship is not consistent, you must specify the -force parameter when you restart the relationship. This situation can arise if the relationship had been stopped, and then further input transactions had occurred on the original primary of the relationship. Even though you use of the -force parameter in this situation, the data on the secondary is not be useful for disaster recovery purposes because the relationship is in an inconsistent state.

In the idling state, you must provide the -primary parameter. In other connected states, you can provide the -primary parameter, but it must match the existing setting.

The -force parameter is required if consistency would be lost by starting a copy operation. This can occur if input transactions have occurred on either the primary or secondary VDisks since the ConsistentStopped or Idling state occurred. If the startrcrelationship command is issued without the -force parameter in such circumstances, the command fails. In general, the -force parameter is required if the relationship is in one of the following states:

ConsistentStopped but not synchronized
Idling but not synchronized

The -force parameter is not required if the relationship is in one of the following states:

InconsistentStopped
InconsistentCopying
ConsistentSynchronized

However, the command will not fail if you do specify the -force parameter.

The -clean parameter is used when a Metro Mirror or Global Mirror relationship is started and the secondary VDisk in the relationship is assumed to be clean; any changes made on the secondary VDisk are ignored, and only changes made on the clean primary VDisk are considered when synchronizing the primary and secondary disks. The -clean parameter can be used in the following circumstance:

A relationship is created with the -sync parameter specified. (At this point it does not matter if the primary and secondary disks contain the same data, even though the use of the -sync parameter implies that this is true).
A svctask stoprcrelationship command is issued with the -access parameter specified. This permits access to the secondary disk. Change recording begins at the primary disk.
An image of the primary disk is copied and loaded on to the secondary disk. It is permissible to allow updates to the primary disk during the image copy as this image need only be a fuzzy image of the primary disk.
A svctask startrcrelationship command that specifies the -primary master, -force, and -clean parameters is issued. The auxiliary disk is marked as clean and changes on the master disk that have occurred since the relationship was stopped are copied to the auxiliary disk.
Once the background copy has completed, the relationship becomes consistent and synchronized.

An invocation example

svctask startrcrelationship rccopy1

The resulting output

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