7 Partitioning the Library

Library partitioning reserves library resources (drives, slots, and CAPs) for the exclusive use of specified HLI and FC-SCSI hosts. Partitioning is an optional feature enabled in SLC.

See Also

Partitioning Guidelines to Maximize Library Performance

  • Partition storage slots in the largest blocks possible. Cluster cartridges and drives together based on workload. Ensure that each partition has an adequate number of data cartridges, scratch cartridges, and tape drives to support peak workload.

  • Avoid partitioning individual drives and storage cells. Individually select and deselect resources only when you need to fine-tune a partition that has already been broadly defined in larger blocks.

  • Install enough CAPs to provide at least one CAP for each partition. This allows each partition to contain a dedicated CAP.

  • For quicker enter and ejects, partition storage cells close to the CAPs. For quicker access to stored data, partition storage cells close to the drives.

Partitioning the Library Using SLC

Note:

No partitioning changes occur until you apply the changes with the Commit tab. To discard uncommitted changes, click Refresh.

Adding a Partition ID

  1. Stop any host operations.

  2. Select the Tools > Partitions > Summary (Step 2) tab.

  3. In the Partition Allocation Summary area, click Add Partition.

  4. Select the partition ID, enter a name, and then select an interface type. Partition IDs do not need to be consecutive.

  5. Click OK.

  6. Repeat steps 3-5 to add up to eight partitions. For FC-SCSI connections, see "Adding a FC-SCSI Host Connection".

  7. Proceed to "Allocating Resources to a Partition".

Adding a FC-SCSI Host Connection

For FC-SCSI partitions, you must add a host connection (HLI host-partition connections are configured through the host library management software).

  1. Select the Tools > Partitions > Summary (Step 2) tab.

  2. In the Partition Allocation Summary area, select the partition.

  3. Click Add Connection.

  4. Enter the Initiator (WWPN) and LUN. Each initiator connected to the library must have one library partition assigned to LUN 0.

  5. Click OK.

  6. Repeat until you have added all required FC-SCSI connections. Each partition can have up to nine host connections, and each host can connect to multiple partitions.

Deleting a Partition

When you delete a partition, all resources allocated to the partition are marked available, all host connections for the partition are deleted, and the partition ID is deleted.

  1. Move valid data cartridges out of the partition that will be deleted (see "Moving Cartridges (Recovery Moves)").

  2. Select the Tools > Partitions > Summary (Step 2) tab.

  3. In the Partition Allocation Summary area, click the partition to remove.

  4. Click Delete Partition.

    Note:

    If you deleted all the partitions, you must select a library interface type (HLI or FC-SCSI).

  5. Proceed to "Committing Partitioning Changes".

Changing the Partition Interface Type

Caution:

Changing the interface type can result in loss of active host connections or existing shared CAP assignments.

  1. Select the Tools > Partitions > Summary (Step 2) tab.

  2. In the Partition Allocation Summary area, select the partition to modify.

  3. Click Modify Partition.

  4. Proceed to "Committing Partitioning Changes".

Changing FC-SCSI Host Connection Information

  1. Select the Tools > Partitions > Summary (Step 2) tab.

  2. In the Connections section, select the host-partition connection to modify.

  3. Click Modify a Connection.

  4. Proceed to "Committing Partitioning Changes".

Allocating Resources to a Partition

  1. Select the Tools > Partitions > Module Map (Step 3a) tab.

  2. Select a module, and then click the Design (Step 3b) tab.

  3. Select a partition ID from the drop-down list.

  4. In the Select by drop-down list, select a range. Then, select Add or Remove.

  5. Use the library map to select the resources to add or remove. Partitions can be non-contiguous.

    Note:

    To re-assign a resource from one partition to another, you must remove the resource from the initial partition before re-allocating it.

  6. Repeat for each partition ID. When you complete the partition design, click Verify.

    Caution:

    If there are warnings, click Details >> and perform recovery moves on the orphaned cartridges (see "Moving Cartridges (Recovery Moves)"). Then re-verify the design.

  7. If there are no warnings, proceed to see "Committing Partitioning Changes".

Partitioning Icons

SLC Icon Description
Rectangle with X(rectangle with X) Not Accessible — resources not available for host operations (reserved system slot, physically blocked, and so on).
White rectangle(white rectangle) Unallocated — resource available for assignment
Yellow rectangle(yellow rectangle) Partition # — resources assigned to the current partition
Red rectangle(red rectangle) Other Partitions — resources assigned to another partition
Gray rectangle(gray rectangle) Shared CAP — a CAP assigned to multiple partitions

Committing Partitioning Changes

You must complete these procedures to make changes to the library.

Note:

To prevent configuration conflicts, you should make the library unavailable to other users and stop all host operations before committing partitioning changes.

  1. Take the library offline to the host (see your host software documentation).

  2. Click the Commit (Step 4) tab of the Partitions interface.

  3. Click Apply.

    Note:

    If the Apply button is grayed out, the library capacity is over-subscribed. Remove storage slots from a partition or purchase more capacity.

    Caution:

    If there are warnings, click Details >> and perform recovery moves on the orphaned cartridges (see "Moving Cartridges (Recovery Moves)").

  4. Configure all affected library host applications (see the host software documentation and "Updating Hosts After Modifying Partitioning").

Viewing Current Partition Allocations

See also "Viewing Partitioning Reports".

  1. Select the Tools > Partitions > Module Map (Step 3a) tab.

  2. Click a module to display.

  3. Click the Current Partition Definitions tab. Hover over a resource to display detailed information.

Partitioning CAPs

Note:

AEM CAPs are subject to the same partitioning rules and restrictions as rotational CAPs. The term CAP refers to both types of CAPs, unless otherwise specified.

Each partition can have either dedicated CAPs or shared CAPs, but not both. Only partitions with the same host interface type (FC-SCSI or HLI) can share a CAP. Only one partition at a time can use a shared CAP.

For information about CAP states in a partitioned library, see "CAP States".

Reserving a CAP in HLI Partitions

An HLI host can reserve a CAP if the CAP is empty, closed, locked, and not already reserved. Each HLI host reserves a CAP for exclusive use as needed, then releases the CAP when it is no longer required.

If the host does not release the CAP reservation and you cannot terminate the enter or eject operation in ACSLS or ELS, you can override the host partition reservation (see "Overriding a Partition CAP Reservation").

Associating a CAP to an FC-SCSI Partition

Most FC-SCSI hosts typically assume sole ownership of a CAP. Therefore, when using a shared CAP to enter or eject cartridges, you must manually associate a CAP to the partition (see "Assigning Ownership of a Shared CAP to an FC-SCSI Partition").

Resolving Orphaned Cartridges Caused by Partitioning Changes

In partitioned libraries, an orphaned cartridge is located in a slot not allocated to the original host. Orphaned cartridges can occur when you change the size of a partition, delete a partition, or move a cartridge to a slot or drive that is not allocated to a partition.

In a partitioned library, orphaned cartridges can cause data loss. A host that finds an orphaned cartridge in its partition may treat the cartridge as a scratch volume and overwrite the data.

To resolve orphaned cartridges, you can:

For non-partitioned libraries, see "Resolving Orphaned Cartridges Caused by Capacity Changes".