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.
A 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.
For 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.
Fields
- Replicated mirror group name
Specify 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. 
- Recovery action
Specifies 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
Select 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: 
Automatic recovery
is not supported for mirror groups that are enabled for HyperSwap® operations.


- Manual
Select 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.

- 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:
Synchronous
Select 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.

Asynchronous
Select 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.
- HyperSwap
Select 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.
Mirror group type:
Select 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.
Consistency enabled
Select 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. 
- Global mirror session ID
Select 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.
- Max coordination time (ms)
Specify 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.
- 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
Select 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.
- 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
Select 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.
Node name
Select 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.
- Disk other than HyperSwap disk
Select 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.
HyperSwap disk
Select 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.
- Consistency group
Select 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.
Unplanned HyperSwap timeout (sec)
Specify 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.
- HyperSwap priority
Select 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.
- 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.