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Modify consistency group geometry

Contributors netapp-ahibbard
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Beginning with ONTAP 9.13.1, you can modify the geometry of a consistency group. Modifying the geometry of a consistency group enables you to alter the configuration of child or parent consistency groups without disruption to ongoing IO operations.

Modifying consistency group geometry has an impact on existing Snapshot copies of the consistency group. For details, refer to the specific modification to geometry you want to perform.

Note You cannot modify the geometry of a consistency group that is configured with a remote protection policy. You must first break the protection relationship, modify the geometry, then restore remote protection.

Add a new child consistency group

Beginning with ONTAP 9.13.1, you can add a new child consistency group to an existing parent consistency group.

About this task

  • A parent consistency group can contain a maximum of five child consistency groups. See consistency group limits for other limits.

  • You cannot add a child consistency group to a single consistency group. You must first promote the consistency group, then you can add a child consistency group.

  • Existing Snapshot copies of the consistency group captured before the expand operation will be considered partial. Any restore operation based on that Snapshot copy will reflect the consistency group at the point-in-time of the Snapshot copy.

Example 1. Steps
System Manager

Beginning with ONTAP 9.13.1, you can perform this operation with System Manager.

Add a new child consistency group

  1. Select Storage > Consistency groups.

  2. Select the parent consistency group you want to which you want to add a child consistency group.

  3. Next to the parent consistency group's name, select More then Add new child consistency group.

  4. Enter a name for your consistency group.

  5. Choose whether you would like to add new or existing volumes.

    1. If you are adding existing volumes, select Existing volumes then choose the volumes from the dropdown menu.

    2. If you are adding new volumes, select New volumes then designate the number of volumes and their size.

  6. Select Add.

CLI

Beginning with ONTAP 9.14.1, you can add a child consistency group using the ONTAP CLI.

Before you begin

  • You must be at the admin privilege level to perform this task.

  • In ONTAP 9.14.1, you must be a cluster or SVM administrator to perform this task. Beginning with ONTAP 9.15.1, any user at the admin privilege level can perform this task.

Add a child consistency group with new volumes

  1. Create the new consistency group. Provide values for the consistency group name, volume prefix, number of volumes, volume size, storage service, and export policy name:

    consistency-group create -vserver SVM_name -consistency-group consistency_group -parent-consistency-group parent_consistency_group -volume-prefix prefix -volume-count number -size size -storage-service service -export-policy policy_name

Add a child consistency group with existing volumes

  1. Create the new consistency group. The volumes parameter accepts a comma-separated list of volume names.

    consistency-group create -vserver SVM_name -consistency-group new_consistency_group -parent-consistency-group parent_consistency_group -volumes volume

Detach a child consistency group

Beginning with ONTAP 9.13.1, you can remove a child consistency group from its parent, converting it into an individual consistency group.

About this task

  • Detaching a child consistency group causes the parent consistency group's Snapshot copies to become invalid and inaccessible. Volume granular Snapshot copies remain valid.

  • Existing Snapshot copies of the individual consistency group remain valid.

  • This operation will fail if there is an existing single consistency group that has the same name as the child consistency group you intend to detach. If you encounter this scenario, you must rename the consistency group when you detach it.

Example 2. Steps
System Manager

Beginning with ONTAP 9.13.1, you can perform this operation with System Manager.

Detach a child consistency group

  1. Select Storage > Consistency groups.

  2. Select the parent consistency group that contains the child you want to detach.

  3. Next to the child consistency group you want to detach, select More then Detach from parent.

  4. Optionally, rename the consistency group and select an application type.

  5. Select Detach.

CLI

Beginning with ONTAP 9.14.1, you can detach a child consistency group using the ONTAP CLI.

Before you begin

  • You must be at the admin privilege level to perform this task.

  • In ONTAP 9.14.1, you must be a cluster or SVM administrator to perform this task. Beginning with ONTAP 9.15.1, any user at the admin privilege level can perform this task.

Detach a child consistency group

  1. Detach the consistency group. Optionally, rename the detached consistency group with the -new-name parameter.

    consistency-group detach -vserver SVM_name -consistency-group child_consistency_group -parent-consistency-group parent_consistency_group [-new-name new_name]

Move an existing single consistency group under a parent consistency group

Beginning with ONTAP 9.13.1, you can convert an existing single consistency group to a child consistency group. You can either move the consistency group under an existing parent consistency group or create a new parent consistency group during the move operation.

About this task

  • The parent consistency group must have four or fewer children. A parent consistency group can contain a maximum of five child consistency groups. See consistency group limits for other limits.

  • Existing Snapshot copies of the parent consistency group captured before this operation are considered partial. Any restore operation based on one of those Snapshot copies reflects the consistency group at the point-in-time of the Snapshot copy.

  • Existing consistency group Snapshot copies of the single consistency group remain valid.

Example 3. Steps
System Manager

Beginning with ONTAP 9.13.1, you can perform this operation with System Manager.

Move an existing single consistency group under a parent consistency group

  1. Select Storage > Consistency groups.

  2. Select the consistency group you want to convert.

  3. Select More then Move under different consistency group.

  4. Optionally, enter a new name for the consistency group and select a component type. By default, the component type will be Other.

  5. Choose if you want to migrate to an existing parent consistency group or create a new parent consistency group:

    1. To migrate to an existing parent consistency group, select Existing consistency group then choose the consistency group from the dropdown menu.

    2. To create a new parent consistency group, select New consistency group then provide a name for the new consistency group.

  6. Select Move.

CLI

Beginning with ONTAP 9.14.1, you can move a single consistency group under a parent consistency group using the ONTAP CLI.

Before you begin

  • You must be at the admin privilege level to perform this task.

  • In ONTAP 9.14.1, you must be a cluster or SVM administrator to perform this task. Beginning with ONTAP 9.15.1, any user at the admin privilege level can perform this task.

Move a consistency group under a new parent consistency group

  1. Create the new parent consistency group. The -consistency-groups parameter will migrate any existing consistency groups to the new parent.

    consistency-group attach -vserver svm_name -consistency-group parent_consistency_group -consistency-groups child_consistency_group

Move a consistency group under an existing consistency group

  1. Move the consistency group:

    consistency-group add -vserver SVM_name -consistency-group consistency_group -parent-consistency-group parent_consistency_group

Promote a child consistency group

Beginning with ONTAP 9.13.1, you can promote a single consistency group to a parent consistency group. When you promote the single consistency group to a parent, you also create a new child consistency group that inherits all of the volumes in the original, single consistency group.

About this task

  • If you want to convert a child consistency group to a parent consistency group, you must first detach the child consistency group then follow this procedure.

  • Existing Snapshot copies of the consistency group remain valid after you promote the consistency group.

System Manager

Beginning with ONTAP 9.13.1, you can perform this operation with System Manager.

Promote a child consistency group

  1. Select Storage > Consistency groups.

  2. Select the consistency group you want to promote.

  3. Select More then Promote to parent consistency group.

  4. Enter a Name and select a Component type for the child consistency group.

  5. Select Promote.

CLI

Beginning with ONTAP 9.14.1, you can move a single consistency group under a parent consistency group using the ONTAP CLI.

Before you begin

  • You must be at the admin privilege level to perform this task.

  • In ONTAP 9.14.1, you must be a cluster or SVM administrator to perform this task. Beginning with ONTAP 9.15.1, any user at the admin privilege level can perform this task.

Promote a child consistency group

  1. Promote the consistency group. This command will create one parent and one child consistency group.

    consistency-group promote -vserver SVM_name -consistency-group existing_consistency_group -new-name new_child_consistency_group

Demote a parent to a single consistency group

Beginning with ONTAP 9.13.1, you can demote a parent consistency group to a single consistency group. Demoting the parent flattens the hierarchy of the consistency group, removing all associated child consistency groups. All volumes in the consistency group will remain under the new, single consistency group.

About this task

  • Existing Snapshot copies of the parent consistency group remain valid after you demote it to a single consistency. Existing Snapshot copies of any of the associated child consistency groups of that parent become invalid upon demotion. The individual volume Snapshot copies within the child consistency group continue to be accessible as volume-granular Snapshot copies.

Example 4. Steps
System Manager

Beginning with ONTAP 9.13.1, you can perform this operation with System Manager.

Demote a consistency group

  1. Select Storage > Consistency groups.

  2. Select the parent consistency group you want to demote.

  3. Select More then Demote to single consistency group.

  4. A warning will advise you that all associated child consistency groups will be deleted and their volumes will be moved under the new single consistency group. Select Demote to confirm you understand the impact.

CLI

Beginning with ONTAP 9.14.1, you can demote a consistency group using the ONTAP CLI.

Before you begin

  • You must be at the admin privilege level to perform this task.

  • In ONTAP 9.14.1, you must be a cluster or SVM administrator to perform this task. Beginning with ONTAP 9.15.1, any user at the admin privilege level can perform this task.

Demote a consistency group

  1. Demote the consistency group. Use the optional -new-name parameter to rename the consistency group.

    consistency-group demote -vserver SVM_name -consistency-group parent_consistency_group [-new-name new_consistency_group_name]