Create Replicated Mirror Group Wizard: Configure replicated mirror groups

Use this page to provide property settings for the replicated mirror group that you are creating.

Provide the appropriate information to configure the replicated mirror group for the storage system to which it corresponds. The amount and type of information that you need to provide to configure each mirror group vary based on the storage type of the storage system.

start of changeA mirror group is a single entity, equivalent to a consistency group, and consists of a group of disks that use storage-based replication. You can assign the mirror group, as a single entity, to a resource group for use by PowerHA® SystemMirror.end of change

start of changeFor more information about replicated mirroring, see the Storage-based high availability and disaster recovery for PowerHA SystemMirror Enterprise Edition topic in the AIX® Information Center.end of change

Fields

Replicated mirror group name
start of changeSpecify a unique name for the replicated mirror group that you are creating. The name that you specify must consist of 1 - 64 characters. You can use characters of A - Z and a - z, numbers of 0 - 9, and the underscore (_) character. end of change
Recovery action
start of changeSpecifies the disaster recovery policy for PowerHA SystemMirror to use. If there is a real or perceived site outage, PowerHA SystemMirror uses this value to determine whether to automatically start the workload. Select the recovery method to use for the dependent resource group, of which the mirror group is a member, when the primary site goes offline:
Automatic
start of changeSelect this option to have the resource group fall over to the secondary site automatically if the dependent resource in the primary site goes offline.
Note: start of changeAutomatic recovery is not supported for mirror groups that are enabled for HyperSwap® operations.end of change
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Manual
start of changeSelect this option to have the resource group go into the ERROR state, if the dependent resource in the primary site goes offline. PowerHA SystemMirror takes this action instead of having the resource group fall over automatically to the secondary site. The dependent resource group remains in this state until you run a command to fall over to the secondary site and run another command to bring the dependent resource online on the secondary site. This option is the default value.end of change
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Mirror type
Select the replication type that is configured on the storage unit for the disk pair or disk pairs that you specified for this storage unit. You can choose one of the following replication types:
start of changeSynchronousend of change
start of changeSelect this option if the storage unit is configured to perform synchronous replication for the disks that you are including in this mirror group. If you select this option, the storage units perform synchronous replication for the disks included in this mirror group. Synchronous replication is more limited in the distance that is allowed between the storage units than the distance that is allowed by asynchronous replication. However, synchronous replication provides a lower risk of data loss in a disaster situation.

For IBM® DS-Series Metro Mirror (In-band), IBM DS-Series Global Mirror, and IBM System Storage® SAN Volume Controller (SVC) storage systems, synchronous replication is known as Metro Mirror. This option is the default value. If the storage type is DS-Series, you cannot change this value.

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start of changeAsynchronousend of change
start of changeSelect this option if the disks that you are including in this mirror group are configured to use storage-based asynchronous mirroring. If you select this option, the storage units perform asynchronous replication for the disks that are included in this mirror group. Asynchronous replication can be used over longer distances than synchronous replication. However, asynchronous replication also has a higher risk of data loss in a disaster situation. For DS-Series Global Mirror and SVC storage systems, asynchronous replication is known as Global Mirror.end of change
HyperSwap
start of changeSelect whether to enable or disable HyperSwap capabilities for the mirror group. This property is available for only the DS-Series Metro Mirror (In-band) storage type.end of change
start of changeMirror group type:end of change
start of changeSelect the mirror group type. You can select one of the following values:
User
A user mirror group is one that is related to application workloads and is a part of a related resource group. User mirror groups can be concurrently active on multiple nodes, depending on the user configuration. Therefore, you need to perform the HyperSwap operation on a user mirror group in a coordinated manner. A user is activated on a node only if the corresponding resource group is activated on the node.

If Disabled is the value for the HyperSwap property, you must select this mirror group type.

System
A system mirror group is a set of disks that are critical to a single AIX node. This set of disks are either a set of raw disks or a set of volume groups. Examples of such a volume group are the rootvg mirror group or a mirror group that contains the paging device for the node. By definition, a system mirror group is active only on a single node. Therefore, a HyperSwap operation for such disks does not require any coordination with other nodes.

A system mirror group is never acquired from another site, which means that the Recovery action property does not apply to this type of mirror group.

Repositories
A cluster repository mirror group represents disks that are used for the Cluster Aware AIX (CAA) cluster repository. These disks, although shared between multiple nodes, cannot be spread across sites. The system cannot have more than one of these mirror groups.

The Recovery action property does not apply to this type of mirror group.

This property is available only for the DS-Series Metro Mirror (In-band) storage type.end of change
start of changeConsistency enabledend of change
start of changeSelect one of the following options to indicate whether to enable the consistency property for the mirror group:
Yes
Strict write ordering is maintained for the replication. This value ensures that updates to the primary copy of the data are in the same order on the secondary copy. This option is the default value.
No
Strict write ordering is not maintained, which can cause the data to be inconsistent in some cases. Some software, such as relational databases, might be able to recover and resolve the inconsistency, but doing so usually involves a much longer startup time.
This property is available only for DS-Series Metro Mirror (In-band) and EMC Symmetrix storage types. end of change
Global mirror session ID
start of changeSelect a hexadecimal value in the range 00 - ff for the existing Global Mirror session that is configured on the primary and auxiliary storage systems. This property is available only for the DS-Series Global Mirror storage type.end of change
Max coordination time (ms)
start of changeSpecify the time interval, in milliseconds (ms), to wait for a host-driven write I/O operation to complete successfully. This interval is the maximum period allowed for the operation when that operation is impacted due to coordination and serialization activities for the global copy source volumes that belong to the Global Mirror session. The default value is 50 ms. This property is available only for the DS-Series Global Mirror storage type.end of change
Max drain time
Specify the maximum time allowed, in seconds, for draining the out-of-sync bitmap for each iteration of consistency group formation. The default value is 30 seconds. This property is available only for the DS-Series Global Mirror storage type.
Consistency group interval
Specify the amount of time, in seconds, to wait before the formation of the next consistency group. A value of zero (0) means that consistency group formation happens constantly. The default value is 0 seconds. This property is available only for the DS-Series Global Mirror storage type.
XIV consistency group name
start of changeSelect the name of the consistency group that is defined on the IBM XIV® storage unit that corresponds to this mirror group. This property is available only for the IBM XIV storage type.end of change
Storage systems (DS-Series Global Mirror)
Storage system for site 1 (XIV)
Storage system for site 2 (XIV)
Select the storage system where the disks in this replicated mirror group are located. This list consists of storage systems that exist in the cluster. This property is available only for the DS-Series Global Mirror and XIV storage types.
Hitachi Device Group Names
EMC Device Group Names
Select the names of the device groups to participate in this mirror group. The device group selection varies based on the corresponding storage system type on which the device groups are defined. This property is available only for the Hitachi/HP and EMC storage types.
Hitachi Open Remote Copy Manager (HORCM) instance
Specify the instance name of the Hitachi Open Remote Copy (HORC) Manager. This name must match the name of the configuration file on each node. For example, if you use the horcm0.conf file to define your Hitachi disk pairs, specify a value of horcm0 for this property. This property is available only for the Hitachi/HP storage type.
HORC takeover timeout
Specify the amount of time, in seconds, for how long PowerHA SystemMirror waits before the Hitachi Secondary Volume (S-VOL) takeover operation is considered as failed. The default value is 300 seconds. This property is available only for the Hitachi/HP storage type.
HORC pair event waiting timeout
Specify the time, in seconds, to wait for the Hitachi disk pair to reach a stable state. The default value is 3600 seconds. This property is available only for the Hitachi/HP storage type.
Volume group names
Displays the volume groups that are part of the mirror disk pairs in this mirror group. This property is available only for the DS-Series Metro Mirror (In-band) storage type and only when User or System is the value for the Mirror group type property.
Site names
Displays the names of the sites for this mirror group. This property is available only for the DS-Series Metro Mirror (In-band) storage type and only when Repositories is the value for the Mirror group type property.
Raw disks
start of changeSelect one or more raw hard disks that are not included in the specified Volume groups to use in the mirror group. A raw disk is a storage disk that is not allocated to a PowerHA SystemMirror volume group. This property is available only for the DS-Series Metro Mirror (In-band) storage type and only when either User or System is the value for Mirror group type.end of change
start of changeNode nameend of change
start of changeSelect the node on which to locate the new replicated mirror group. This property is available only for the DS-Series Metro Mirror (In-band) storage type and only when System is the value for the Mirror group type.end of change
Disk other than HyperSwap disk
start of changeSelect a hard disk to use in the mirror group that you want to be reserved from use by the HyperSwap operation. This disk is used as the repository if the HyperSwap property for the mirror group is disabled. This property is available only for the DS-Series Metro Mirror (In-band) storage type and only when Repositories is the value for Mirror group type property.end of change
start of changeHyperSwap diskend of change
start of changeSelect a hard disk to use in the mirror group for performing HyperSwap operations. This disk is used as the repository disk when the HyperSwap property for the mirror group is enabled. This property is available only for the DS-Series Metro Mirror (In-band) storage type and only when Repositories is the value for Mirror group type property.end of change
Consistency group
start of changeSelect a value to indicate how PowerHA SystemMirror handles group consistency for the mirror group. If you select enabled, PowerHA SystemMirror enforces group consistency. This property is available only for the DS-Series Metro Mirror (In-band) storage type.end of change
start of changeUnplanned HyperSwap timeout (sec)end of change
start of changeSpecify a time, in seconds, to indicate how long PowerHA SystemMirror waits before an unplanned HyperSwap operation is considered as failed. You cannot specify a value for this property if Disabled is the value for the HyperSwap property. This property is available only for the DS-Series Metro Mirror (In-band) storage type.end of change
HyperSwap priority
start of changeSelect a value to indicate the priority for a HyperSwap operation for this mirror group. You can select a value of High, Medium, or Low. For a planned HyperSwap operation, PowerHA SystemMirror swaps mirror groups based on the priority that you select. This property is available only for the DS-Series Metro Mirror (In-band) storage type.end of change
Mirror disk pairs
Select the mirror disk pairs to associate with this mirror group. This property is available only for the SVC storage type.

Actions

Add Another
Click Add Another to add another set of properties so that you can configure another replicated mirror group. All fields for the added mirror group are inactive until you specify information for the Replicated mirror group name property.
Remove
Click Remove to remove the content from the first set of replicated mirror group properties and disable all fields after the Replicated mirror group name property. If applied to an added mirror group on the page, this action removes the entire set of properties for the added mirror group.