Add a Configured Array to a Group (Group Merge)

A configured array is a group of one. Therefore, adding a configured array to a group is the same procedure as merging two groups of arrays. You can merge two groups of arrays that are accessed with either iSCSI, Fibre Channel, or multiprotocol (both iSCSI and Fibre Channel). The array that is being merged into the target is the source group, and the target array is the destination group.

Before you merge two groups, verify the following requirements.

Platform Compatibility Notes:

• You cannot merge two groups of arrays that have different access protocols. Both groups must use iSCSI, Fibre Channel, or iSCSI and Fibre Channel (multiprotocol).
• You can add multiple FC arrays to the same group.
  • Array OS 3.x.x.x or later is required.
  • Fibre Channel WWPNs will change for the array added to the group. You must adjust zoning appropriately to reflect this.
• All Flash (AFA), Hybrid Flash (HFA), and Secondary Flash (SFA) arrays can be merged into the same multi-array group.
  • Pools of different array types ( AFA, HFA, and SFA ) cannot be merged into a single multi-array pool.
  • Only pools from the same array type can be merged into a multi-array pool.
• To move data from one array to another, you can add an AFA to an existing HFA or SFA group, migrate to the AFA using volume move, and remove the old array non-disruptively.
  • Array OS 4.x.x.x or later is required.
  • For more information, see KB-000277 Array Data Migration
• To move data from one array to another, you can add an HFA or SFA to an existing AFA group, migrate from the HFA or SFA to AFA, and remove the HFA or SFA array.
  • This process is disruptive to host I/O since this iSCSI arrays will undergo a discovery IP change.
• If the same CHAP username is configured on both the source and destination groups, only the CHAP user on the destination array will be used after the merge.
• If secure shell (SSH) keys exist for users of the same name on source and destination groups, the SSH keys for the destination group will be used. SSH keys for the user in the source group will be discarded.

Verify the following:

• Both groups use the same data and management subnets.
  • All array groups to be merged must have the same subnets defined using the same subnet names
  • All interfaces assigned to a given subnet must be able to reach each other, regardless of which array they are located on.
  • All interfaces within a given subnet must be within the same broadcast domain (the L2 or layer 2 network segment).
  • All interfaces in a particular subnet must be in the same VLAN, and any inter-switch links that exist between those interfaces must be configured to allow the same VLAN
  • The array will have one or more subnets tagged as Allow Group. For any subnet where Allow Group is set to Yes, the switch ports connected to those arrays need to also be in the same native VLAN.
  • No more than four data subnets can exist.
• Both groups use the same data protocol (iSCSI, Fibre Channel, or multiprotocol) and the data ports must be connected.
  NOTE:

  If necessary, you can modify the management subnet to carry data and management traffic.

  Data Discovery IP addresses must be added for group traffic between the arrays.

• All arrays to be merged that have Active Directory integration enabled must be configured to use the same Active Directory domain for authentication.
• Both arrays are in an active or standby state.
• Both arrays have the same array OS version.
  • If they do not, update one or both arrays. To learn more about updating the array OS, see Updates.
• Not more than one of the groups contains partners with synchronous replication.
• Throttle levels are the same for both groups.
  • Group-level throttles from the joining group are automatically discarded and the hosting group throttles are automatically applied. If the throttle levels are set differently on the two arrays that are associated with the source and destination groups, adjust the throttle level on the destination group based on your environment and requirements.
• Arrays must have the same maximum transmission unit (MTU) setting on configured subnets.
• Switches and inter-switch links must have their MTUs set to a value equal to or greater than the MTU used on group members.
  • Note that some switches require that the MTU be set higher than the value on the array, due to differences in how they calculate the value of the MTU.
  • There are no consequences to setting the switch MTU to the largest reasonable value, often as high as 9214 or 9216 bytes.
• Both groups must be on the same L2 network or broadcast domain

  Both groups must also be in the same VLAN, on the same switch or switch-stack, or on switches connected via an inter-switch link or trunk.

Notes on Names:

• All array names in your environment must be unique.
• iSCSI subnet label names on both arrays must be the same.
• Group names must be unique and short enough to avoid truncation when merged.
• The group name must be different from the name of the array being added.
• Volume names cannot be re-used on the source and destination groups.
• All initiator group names must be unique.
  • Initiator IQNs on the source and destination, if matching, must also use the same case.
• All protection schedule names must be unique.
• The names for all new pools must contain fewer than 64 characters, if you intend to merge two groups.
  • If the name of the source group is short enough to form a new pool name that is less than 64 characters, then truncation does not occur. However, if the source group has a long name, such as a 63-character name, then the new pool name results in more than 64 characters. In this case, the name is automatically truncated to the limit of 64 characters.
• Other than the default pool, pool names on the source and destination groups must be unique.
  • The default pool on the source group will be renamed default-source_group_name.
  • A group named default-source_group_name cannot exist on the destination group.