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:

ADPv2 is supported in MetroCluster IP configurations.
The root aggregate must be located in Partition 3 for all nodes on both sites.
Partitioning and disk assignment are performed automatically during the initial configuration of the MetroCluster sites.
Pool 0 disk assignments are done at the factory.
The unmirrored root is created at the factory.
Data partition assignment is done at the customer site during the setup procedure.
In most cases, drive assignment and partitioning is done automatically during the setup procedures.
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-Node01

Partition 1:

ClusterA-Node01

Partition 2:

ClusterA-Node02

Partition 3:

ClusterA-Node01

Drive/Partition	Owner
Drive:	`ClusterA-Node01`
Partition 1:	`ClusterA-Node01`
Partition 2:	`ClusterA-Node02`
Partition 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.

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.

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:

All of the disks on site_A-shelf_1 are automatically assigned to pool 0 of node_A_1
All of the disks on site_A-shelf_3 are automatically assigned to pool 0 of node_A_2
All of the disks on site_B-shelf_1 are automatically assigned to pool 0 of node_B_1
All of the disks on site_B-shelf_3 are automatically assigned to pool 0 of node_B_2
All of the disks on site_B-shelf_2 are automatically assigned to pool 1 of node_A_1
All of the disks on site_B-shelf_4 are automatically assigned to pool 1 of node_A_2
All of the disks on site_A-shelf_2 are automatically assigned to pool 1 of node_B_1
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…
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 36-48	Bays 36-41

The 48 drive bays are divided into four quarters:

Install six drives in the first six bays in each quarter…

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 36-48

Bays 36-41

If you are using two 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.

Related information

Required MetroCluster IP components and naming conventions

Disk and aggregate management

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

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.

Half of the internal drives remain unassigned before MetroCluster is configured.

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:

Three partitions for data
Two parity partitions
One spare partition

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:

If owned by the local node, pool0 is used.
If owned by the remote node, pool1 is used.

For example: a shelf with quarters Q1 through Q4 can have following assignments:

Q1: node_A_1 pool0
Q2: node_A_2 pool0
Q3: node_B_1 pool1
Q4:node_B_2 pool1

Half of the internal drives remain unassigned before MetroCluster is configured.

Each of the two plexes in the root aggregate includes the following partitions:

Two partitions for data
Two parity partitions
No spares

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: Eight partitions for data Two parity partitions Two spare partitions
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: Two partitions for data Two parity partitions No spare partitions

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:

Eight partitions for data
Two parity partitions
Two spare partitions

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:

Two partitions for data
Two parity partitions
No spare partitions

ADP and disk assignment on ETERNUS AX4100 and ETERNUS AX4100 ASA

BURT 1384407

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: 20 partitions for data Two parity partitions Two spare partitions
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: Three partitions for data Two parity partitions One spare partition

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:

20 partitions for data
Two parity partitions
Two spare partitions

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:

Three partitions for data
Two parity partitions
One spare partition

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

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

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