startrcconsistgrp

Use the startrcconsistgrp command to start the Global Mirror, Metro Mirror, or active-active consistency group copy process, set the direction of copy if it is undefined, and optionally mark the secondary volumes of the consistency group as clean.

Syntax

startrcconsistgrp [ -primary { master | aux } ] [ -force ] [ -clean ] { rc_consist_group_id | rc_consist_group_name }

Parameters

-primarymaster | 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 consistency group 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 consistency group is in the ConsistentStopped state, but is not synchronized or is in the idling state - except if consistency protection is configured.
-clean: (Optional) Specifies that the volume that is to become a secondary is clean for each of the relationships belonging to the group; any changes made on the secondary volume are ignored, and only changes made on the clean primary volume are considered during synchronization of the primary and secondary disks. The consistency group must be in an Idling (connected) state for this parameter to work.
Attention: This flag should only be used if all data changed on the secondary volumes while the consistency group was in the idling state matches the state of the primary volumes when the consistency group was stopped. Otherwise, relationships that are not consistent are reported as consistent. Once this has been done there is no method to determine whether these volumes ever reach a true consistent state until a full background copy can be carried out again.
rc_consist_group_id | rc_consist_group_name: (Required) Specifies the ID or name of the consistency group to start.

Description

This command starts a Global Mirror, Metro Mirror, or active-active stand-alone consistency group. You cannot use this command to start a remote copy relationship if the primary volume is a target volume of a prepared FlashCopy mapping.

This command can only be issued to a consistency group that is connected. For a consistency group 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 an I/O error.

Note: You cannot start a consistency group if it contains a relationship with primary and secondary volumes that are different sizes.

If an existing remote copy relationship is stopped with -access specified but is restarted and the resultant secondary volume (depending on the choice of primary) is mapped to a host of type hide_secondary, that volume is not presented to the host. This is true even though it is mapped for configuration purposes. The mapped volumes are presented to the host if the:

Host type is changed to a type other than hide_secondary
Remote copy relationship is stopped and -access is specified
Volume ceases to be a secondary volume because the remote copy relationship is being deleted or switched

If the resumption of the copy process leads to a period of time when the relationship is not consistent, then 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 been performed on the original primary disk of the relationship. When you use the -force parameter in this situation, the data on the secondary disk is not usable (because it is inconsistent) in a disaster recovery circumstance.

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 write operations on either primary or secondary volumes have taken place since the ConsistentStopped or idling state occurred. If the command is issued without the -forceparameter in such circumstances, the command fails . In general, the -force parameter is required if the group is in one of the following states:

Consistent_Stopped but not synchronized (sync=out_of_sync)
Idling but not synchronized

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

Inconsistent_Stopped
Inconsistent_Copying
Consistent_Synchronized

The command does not fail if you specify the -force parameter.

When you configure a secondary change volume on all relationships in a consistency group, the consistency group goes into a consistent_copying state during resynchronization. If you specify startrcconsistgrp for a consistency group in an idling state, consistency protection is disabled if any of the secondary volumes have been written to. This means that you must specify the -force parameter.

The -clean parameter is used when a Global Mirror or Metro Mirror group is started and the secondary volumes in this group are assumed to be clean, which means that any changes that have been made at the secondary are ignored and only changes made at the primary are considered when synchronizing the primary and secondary volumes. The -clean parameter can be used in the following scenario:

A consistency group is created with the -sync parameter. At this point, it does not matter if the primary and secondary contain the same data, even though the use of the -sync parameter implies that this is true.
A stoprcconsistgrp command is issued with the -access parameter. This permits access to the secondary disk. Change recording begins at the primary.
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 can be only a fuzzy image of the primary disk.
A startrcconsistgrp 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, relationships in the group become consistent and synchronized.

After restarting a consistency group in either of these states (Idling or multi), the data on the secondary volumes is not usable for disaster recovery until the consistency group becomes consistent.

A Global Mirror consistency group with a cycling_mode of multi in either of these states does not require the -force parameter because consistent secondary images are retained. However, if such a consistency group is in idling state and written data has been received at any secondary volume in the consistency group, the -force flag is still required, because the secondary volumes have a divergent image that cannot represent a consistent earlier state.

A Global Mirror relationship with a cycling mode of:

none uses the non-cycling Global Mirror algorithm
multi must have a change volume configured at the primary volume (or the command fails)
multi must also have a change volume configured at the secondary volume (or the command fails)
multi performs multiple cycles of cycling

After creating a background copy the relationship remains in copying state, waiting for the remainder of the period time to expire before performing a new cycle. If the secondary change volume is deconfigured when the background copy completes, the relationship stops as if there is no cycle period.

Relationships that are active-active must have a state of idling to be started.

An invocation example

startrcconsistgrp rccopy1

The resulting output:

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