MetroCluster Manuals ( CA08871-401 )
Considerations for automatic drive assignment and ADP systems
MetroCluster IP configurations support new installations using ADP (Advanced Drive Partitioning).
You should be aware of the following considerations when using ADP with MetroCluster IP configurations:
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ONTAP 9.7 and later is required to use ADP with MetroCluster IP configurations.
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ADPv2 is supported in MetroCluster IP configurations.
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The root aggregate must be located in Partition 3 for all nodes on both sites.
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Partitioning and disk assignment are performed automatically during the initial configuration of the MetroCluster sites.
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Pool 0 disk assignments are done at the factory.
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The unmirrored root is created at the factory.
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Data partition assignment is done at the customer site during the setup procedure.
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In most cases, drive assignment and partitioning is done automatically during the setup procedures.
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A disk and all of its partitions must be owned by nodes in the same high-availability (HA) pair. Partition or drive ownership within a single drive cannot be mixed between the local HA pair and the disaster recovery (DR) partner or DR auxiliary partner.
Example of a supported configuration:
Drive/Partition
Owner
Drive:
ClusterA-Node01Partition 1:
ClusterA-Node01Partition 2:
ClusterA-Node02Partition 3:
ClusterA-Node01
Automatic partitioning
ADP is performed automatically during initial configuration of the system.
Automatic assignment of disks must be enabled with the storage disk option modify -autoassign on command.
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You must set the ha-config state to mccip before automatic provisioning to make sure that the correct partition sizes are selected to allow for appropriate root volume size. For more information, see Verifying the ha-config state of components.
A maximum of 96 drives can be automatically partitioned during installation. You can add extra drives after the initial installation.
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If you are using internal and external drives, you first initialize the MetroCluster with only the internal drives using ADP. You then manually connect the external shelf after you complete your installation or setup task. You must ensure that the internal shelves have the recommended minimum number of drives as outlined in ADP and disk assignment differences by system. For both the internal and external drives, you must populate the partially full shelves as described in How to populate partially-full shelves. |
How shelf-by-shelf automatic assignment works
If there are four external shelves per site, each shelf is assigned to a different node and different pool, as shown in the following example:
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All of the disks on site_A-shelf_1 are automatically assigned to pool 0 of node_A_1
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All of the disks on site_A-shelf_3 are automatically assigned to pool 0 of node_A_2
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All of the disks on site_B-shelf_1 are automatically assigned to pool 0 of node_B_1
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All of the disks on site_B-shelf_3 are automatically assigned to pool 0 of node_B_2
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All of the disks on site_B-shelf_2 are automatically assigned to pool 1 of node_A_1
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All of the disks on site_B-shelf_4 are automatically assigned to pool 1 of node_A_2
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All of the disks on site_A-shelf_2 are automatically assigned to pool 1 of node_B_1
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All of the disks on site_A-shelf_4 are automatically assigned to pool 1 of node_B_2
How to populate partially-full shelves
If your configuration is using shelves that are not fully populated (have empty drive bays) you must distribute the drives evenly throughout the shelf, depending on the disk assignment policy. The disk assignment policy depends on how many shelves are at each MetroCluster site.
If you are using a single shelf at each site, disks are assigned using a quarter-shelf policy. If the shelf is not fully populated, install the drives equally on all quarters.
The following table shows an example of how to place 24 disks in a 48 drive internal shelf. The ownership for the drives is also shown.
The 48 drive bays are divided into four quarters: |
Install six drives in the first six bays in each quarter… |
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Quarter 1: Bays 0-11 |
Bays 0-5 |
Quarter 2: Bays 12-23 |
Bays 12-17 |
Quarter 3: Bays 24-35 |
Bays 24-29 |
Quarter 4: Bays 36-47 |
Bays 36-41 |
The following table shows an example of how to place 16 disks in a 24 drive internal shelf.
The 24 drive bays are divided into four quarters: |
Install four drives in the first four bays in each quarter… |
|---|---|
Quarter 1: Bays 0-5 |
Bays 0-3 |
Quarter 2: Bays 6-11 |
Bays 6-9 |
Quarter 3: Bays 12-17 |
Bays 12-15 |
Quarter 4: Bays 18-23 |
Bays 18-21 |
If you are using two external shelves at each site, disks are assigned using a half-shelf policy. If the shelves are not fully populated, install the drives equally from either end of the shelf.
For example, if you are installing 12 drives in a 24-drive shelf, install drives in bays 0-5 and 18-23.
Adding shelves to an existing configuration
Automatic drive assignment supports the symmetrical addition of shelves to an existing configuration.
When new shelves are added, the system applies the same assignment policy to newly added shelves. For example, with a single shelf per site, if an additional shelf is added, the systems applies the quarter-shelf assignment rules to the new shelf.
ADP and disk assignment differences by system in MetroCluster IP configurations
The operation of Advanced Drive Partitioning (ADP) and automatic disk assignment in MetroCluster IP configurations varies depending on the system model.
| In systems using ADP, aggregates are created using partitions in which each drive is partitioned in to P1, P2 and P3 partitions. The root aggregate is created using P3 partitions. |
You must meet the MetroCluster limits for the maximum number of supported drives and other guidelines.
ADP and disk assignment on ETERNUS AX1200 and ETERNUS AX2100 series
Guideline |
Drives per site |
Drive assignment rules |
ADP layout for root partition |
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|---|---|---|---|---|---|
Minimum recommended drives (per site) |
Internal drives only |
The internal drives are divided into four equal groups. Each group is automatically assigned to a separate pool and each pool is assigned to a separate controller in the configuration.
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Two quarters are used by the local HA pair. The other two quarters are used by the remote HA pair. The root aggregate includes the following partitions in each plex:
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Minimum supported drives (per site) |
16 internal drives |
The drives are divided into four equal groups. Each quarter-shelf is automatically assigned to a separate pool. Two quarters on a shelf can have the same pool. The pool is chosen based on the node that owns the quarter:
For example: a shelf with quarters Q1 through Q4 can have following assignments:
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Each of the two plexes in the root aggregate includes the following partitions:
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ADP and disk assignment on ETERNUS AC2100 and ETERNUS AX2200
Guideline |
Drives per site |
Drive assignment rules |
ADP layout for root partition |
|---|---|---|---|
Minimum recommended drives (per site) |
48 drives |
The drives on each external shelf are divided into two equal groups (halves). Each half-shelf is automatically assigned to a separate pool. |
One shelf is used by the local HA pair. The second shelf is used by the remote HA pair. Partitions on each shelf are used to create the root aggregate. The root aggregate includes the following partitions in each plex:
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Minimum supported drives (per site) |
16 internal drives |
The drives are divided into four equal groups. Each quarter-shelf is automatically assigned to a separate pool. |
Each of the two plexes in the root aggregate includes the following partitions:
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ADP and disk assignment on ETERNUS AX4100 series
Guideline |
Drives per site |
Drive assignment rules |
ADP layout for root partition |
|---|---|---|---|
Minimum recommended drives (per site) |
48 drives |
The drives on each external shelf are divided into two equal groups (halves). Each half-shelf is automatically assigned to a separate pool. |
One shelf is used by the local HA pair. The second shelf is used by the remote HA pair. Partitions on each shelf are used to create the root aggregate. The root aggregate includes the following partitions in each plex:
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Minimum supported drives (per site) |
24 drives |
The drives are divided into four equal groups. Each quarter-shelf is automatically assigned to a separate pool. |
Each of the two plexes in the root aggregate includes the following partitions:
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ADP and disk assignment on ETERNUS AC4100 and ETERNUS AX4100 series
Guideline |
Drives per site |
Drive assignment rules |
ADP layout for root partition |
|---|---|---|---|
Minimum recommended drives (per site) |
96 drives |
Drives are automatically assigned on a shelf-by-shelf basis. |
Each of the two plexes in the root aggregate includes:
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Minimum supported drives (per site) |
24 drives |
The drives are divided into four equal groups (quarters). Each quarter-shelf is automatically assigned to a separate pool. |
Each of the two plexes in the root aggregate includes:
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Disk assignment on ETERNUS HX2200 series
Guideline |
Drives per site |
Drive assignment rules |
ADP layout for root partition |
|---|---|---|---|
Minimum recommended drives (per site) |
24 internal drives and 24 external drives |
The internal and external shelves are divided into two equal halves. Each half is automatically assigned to different pool |
Not applicable |
Minimum supported drives (per site) (active/passive HA configuration) |
Internal drives only |
Manual assignment required |
Not applicable |
Disk assignment on ETERNUS HX6100 series
Guideline |
Drives per site |
Drive assignment rules |
ADP layout for root partition |
|---|---|---|---|
Minimum recommended drives (per site) |
48 drives |
The drives on the external shelves are divided into two equal groups (halves). Each half-shelf is automatically assigned to a separate pool. |
Not applicable |
Minimum supported drives (per site) (active/passive HA configuration) |
24 drives |
Manual assignment required. |
Not applicable |
