Data for storage system pools in capacity and relationship reports

You can include general information, capacity data, properties of components, and other information about storage system pools in capacity and relationship reports.

Information about storage systems pools

You can create capacity and relationship reports that include the following information:

Storage Pool Name: The name that was assigned to the pool when it was added to the system.

Capacity and usage data

You can create capacity and relationship reports that include the following information:

Storage Pool Capacity (GiB)

The total amount of storage space in a pool.

Storage Pool Available Space (GiB)

The amount of unused space that is not reserved for volumes in pools that are on the storage system.

IBM Spectrum Control uses the following formula to determine this value:

pool capacity - used space

For XIV systems and IBM Storage Accelerate, this value represents the unallocated physical space in the pool, not the unallocated virtual space. For some storage systems, this value usually includes only the usable capacity, but might also include overhead space if the pool is unformatted.

Storage Pool Assigned Volume Space (GiB)

The amount of space in the pool that is on volumes that are assigned to a server or storage virtualizer.

Storage Pool Unassigned Volume Space (GiB)

The amount of volume space in the pool that is not assigned to a server or storage virtualizer.

Storage Pool Total Volume Capacity (GiB)

The total storage space on all the volumes in a pool, which includes thin-provisioned and standard volumes. For thin-provisioned volumes, this value includes virtual space.

Storage Pool Real Configured Space (GiB)

The amount of storage space that is in an XIV or IBM Storage Accelerate pool that has an associated soft size. The soft size of a pool is the virtual size of a thin-provisioned pool.

Storage Pool Used Volume Space (GiB)

The amount of allocated space that is used by the volumes in a pool, which includes thin-provisioned and standard volumes.

For resources that are running IBM Storage Virtualize, you can preallocate thin-provisioned volume space when volumes are created. For these resources, the Storage Pool Used Space might be different than the Storage Pool Allocated Space for pools that contain thin-provisioned volumes. In other cases, the values for Storage Pool Used Space and Storage Pool Allocated Space are equal.

This value is accurate as of the most recent time that IBM Spectrum Control collected data about a volume. The value in this property might not be 100% accurate for the current state of volumes. This inaccuracy might occur because data collection is run on a set schedule and the used space on volumes can change rapidly.

Storage Pool Real Available Space (GiB)

The amount of unused space that is in an XIV or IBM Storage Accelerate pool that has an associated soft size. The soft size of a pool is the virtual size of a thin-provisioned pool.

Storage Pool Repository Capacity (GiB)

The amount of space on all extents in the repository of a pool. This space can be used to allocate track space-efficient volumes. This attribute applies only to DS8000 storage systems.

Storage Pool Used Repository Space (GiB)

The amount of space on all extents in the repository of a pool that are allocated. This space can be used to allocate track space-efficient volumes. This attribute applies only to the DS8000 storage systems.

Storage Pool Physical Allocation Percentage

The percentage of physical space in a pool that is reserved for volumes. This value is always less than or equal to 100% because you cannot reserve more physical space than is available in a pool.

IBM Spectrum Control uses the following formula to determine the allocation percentage:

(allocated space ÷ pool capacity) × 100

For example, the physical allocation percentage is 25% for a total pool size of 200 GiB. Therefore, the space that is reserved for volumes is 50 GiB.

Storage Pool Virtual Allocation Percentage

The percentage of physical space in a pool that is committed to the total virtual capacity of the volumes in the pool. In thin-provisioned environments, this percentage exceeds 100% if a pool is overcommitted (over-provisioned).

IBM Spectrum Control uses the following formula to determine the allocation percentage:

(total volume capacity ÷ pool capacity) × 100

For example, the allocation percentage is 200% for a total pool size of 15 GiB. Therefore, the virtual capacity that is committed to the volumes in the pool is 30 GiB.

This configuration means that twice as much space is committed than is physically contained in the pool. If the allocation percentage is 100% for the same pool, then the virtual capacity that is committed to the pool is 15 GiB. This configuration means that all the physical capacity of the pool is already allocated to volumes.

An allocation percentage that is higher than 100% is considered aggressive. The pool has insufficient physical capacity to satisfy the maximum allocation for all the thin-provisioned volumes in the pool. In such cases, you can use the value for Storage Pool Shortfall Percentage to estimate how critical the shortage of space is for a pool.

This value is only available for pools with thin-provisioned volumes.

Storage Pool Shortfall Percentage

The percentage of the remaining unallocated volume space in a pool that is not available to be allocated.

The higher the percentage, the more critical the shortfall of pool space.

IBM Spectrum Control uses the following formula to determine this percentage:

(unallocatable space ÷ (virtual capacity − allocated space)) × 100

You can use this percentage to determine when the amount of overcommitted space in a pool reaches a critically high level. For example, the physical space in a pool might be less than the committed virtual space. In this case, the pool does not have enough space to fulfill the commitment to virtual space.

This value represents the percentage of the committed virtual space that is not available in a pool. As more space is used over time by volumes while the pool capacity remains the same, this percentage increases.

For example, the physical capacity of a pool is 70 GiB, however, 150 GiB of virtual space is committed to thin-provisioned volumes. If the volumes are using 50 GiB, then there is still 100 GiB committed to those volumes (150 GiB - 50 GiB). There is only 20 GiB of available pool space (70 GiB - 50 GiB). Because only 20 GiB of pool space is available, 80 GiB of the committed space cannot be allocated (100 GiB - 20 GiB). In this case, the percentage of committed space that cannot be allocated is 80% (80 GiB ÷ 100 GiB × 100).

This value is only available for pools with thin-provisioned volumes.

Storage Pool Allocated Space (GiB)

The amount of space that is reserved for all the volumes in a pool, which includes both thin-provisioned and standard volumes. The space that is allocated for thin-provisioned volumes is less than their virtual capacity, which is shown in the Storage Pool Total Volume Capacity (GiB) property. If a pool does not contain thin-provisioned volumes, this value is the same as the value in the Storage Pool Total Volume Capacity (GiB) property. This value is equal to the value in the Storage Pool Used Volume Space (GiB) property for the following resources:

Resources other than those that are running IBM Storage Virtualize and are configured as back-end storage
Resources that are running IBM Storage Virtualize, are configured as back-end storage, and are not thin-provisioned

Storage Pool Extent Size (MiB)

The size of the extent that was specified when a pool was created. Smaller extent sizes limit the maximum size of the volumes that can be created in a pool. Smaller extent sizes minimize the amount of potentially wasted space per volume.

This value is only available for resources that are running IBM Storage Virtualize and are configured as back-end storage.

Storage Pool Tier Capacity (GiB)

The information that this property shows depends on whether the report includes the Storage Pool Tier Type property:

Report includes Storage Pool Tier Type: Shows the amount of space on solid-state drives and hard disk drives in a pool. The report shows the storage space on solid-state drives and on hard disk drives on different rows.
Report does not include Storage Pool Tier Type: Shows the total storage space on all of the solid-state drives and hard disk drives in a pool.

The tier is configured to be controlled by the Easy Tier function.

This value is only available for resources that are running IBM Storage Virtualize and are configured as back-end storage.

Storage Pool Tier Available Space (GiB)

The information that this property shows depends on whether the report includes the Storage Pool Tier Type property:

Report includes Storage Pool Tier Type: Shows the amount of unused space on solid-state drives and hard disk drives in a pool. The report shows the unused space on solid-state drives and on hard disk drives on different rows.
Report does not include Storage Pool Tier Type: Shows the total unused space on all of the solid-state drives and hard disk drives in a pool.

The tier is configured to be controlled by the Easy Tier function.

This value is only available for resources that are running IBM Storage Virtualize and are configured as back-end storage.

Storage Pool Tier Number of MDisks

The information that this property shows depends on whether the report includes the Storage Pool Tier Type property:

Report includes Storage Pool Tier Type: Shows the number of managed disks on the tier that are solid-state drives or hard disk drives. The report shows the number of managed disks that are solid-state drives and the number that are hard disk drives on different rows.
Report does not include Storage Pool Tier Type: Shows the total number of managed disks on all of the solid-state drives and hard disk drives in a tier.

This value is only available for resources that are running IBM Storage Virtualize and are configured as back-end storage.

Storage Pool Unallocated Volume Space (GiB)

The amount of the Total Volume Capacity in the pool that is not allocated.

IBM Spectrum Control uses the following formula to determine this value:

total volume capacity - allocated space

The space that is allocated for thin-provisioned volumes is typically less than their virtual capacity. Therefore, the unallocated space represents the difference between the virtual capacity and the allocated space for all the volumes in the pool.

Storage Pool Unallocatable Volume Space (GiB)

The amount of space by which the Total Volume Capacity exceeds the physical capacity of a pool.

In thin-provisioned environments, it is possible to over commit (over provision) storage in a pool. If you create volumes with more virtual capacity than can be physically allocated in the pool, you can over commit storage in the pool.

This value represents the amount of volume space that cannot be allocated based on the current capacity of the pool.

Storage Pool Number of MDisks

The number of managed disks in a storage pool.

Storage Pool Compressed Virtual Capacity (GiB)

The total virtual capacity of all the volumes that are compressed in a pool.

Storage Pool Compressed Capacity (GiB)

The amount of storage space that is used by compressed volumes in a pool. For example, if 100 GiB of uncompressed data is compressed, and the size of the compressed data is 20 GiB, the value is 20.

Storage Pool Uncompressed Capacity (GiB)

The amount of storage space that is used if the compressed volume space is uncompressed. For example, if 100 GiB of uncompressed data is compressed, and the size of the compressed data is 20 GiB, the value is 100.

Storage Pool Maximum I/O Capability

The projected maximum number of I/O operations per second for a pool. This value is calculated based on the value in the Storage Pool Back-End Storage Disks property, and on the values in following properties:

Storage Pool Back-End Storage System Type
Storage Pool Back-End Storage RAID Level
Storage Pool Back-End Storage Disk Type

This property applies only to pools on resources that are running IBM Storage Virtualize.

Storage Pool Back-End Storage Disks

The number of physical disks that contribute to the volumes on the back-end storage system. This property applies only to pools on resources that are running IBM Storage Virtualize.

Component properties

You can create capacity and relationship reports that include the following information:

Storage Pool RAID Level

The RAID level of the resource, such as RAID 5 or RAID 10. The RAID level affects the performance and fault tolerance of the volumes that are allocated from the resource.

Storage Pool Is Solid State

Shows whether there are solid-state drives in the pool. This property can contain the following values:

Mixed: The pool contains both hard disk drives and solid-state drives.
Non solid state: The pool contains no solid-state drives.
Solid state: The pool contains a least one solid-state drive.

Storage Pool Is Encrypted

Shows whether the resource is encrypted. If this value is Yes, the resource is encrypted.

Storage Pool Format

Shows the format of the volume or pool. The format can be a Count Key Data (CKD) format, or a fixed block format.

Storage Pool Is Thin Provisioned

Shows whether a pool, volume, or volume copy is thin-provisioned. If this value is Yes, the resource is thin-provisioned.

Storage Pool Logical Subsystem

The logical subsystem (LSS) to which a volume or pool belongs.

Storage Pool Rank Group

The rank group to which a pool is assigned, that is, 0 or 1. This property applies only to the DS8000 storage systems.

Storage Pool Lock Behavior

Shows whether the pool is locked for write operations, or is disabled for both read and write operations when storage space is limited. This property applies only to XIV systems and IBM Storage Accelerate.

Storage Pool Tier

The tier level of pools on storage systems. For example, the tier can be 1, 2, 3, or another tier number.

Storage Pool Custom Tag 1, 2, and 3

User-defined text that is associated with a storage pool. You can add or edit the custom tags for a storage pool on the Properties notebook of the pool.

Storage Pool Is Compression Active

Shows whether the compression feature is enabled on the storage pool. If this value is Yes, the compression feature is enabled.

Storage Pool Back-End Storage System Type

The type of storage system that provides storage space to a pool. This property applies only to pools on resources that are running IBM Storage Virtualize.

Storage Pool Back-End Storage Disk Type

The class and speed of the physical disks that contribute to the volumes on the back-end storage system. This property applies only to pools on resources that are running IBM Storage Virtualize.

Storage Pool Back-End Storage RAID Level

The RAID level of the volumes on the back-end storage system that provide storage space to a pool. This property applies only to pools on resources that are running IBM Storage Virtualize.

Status information

You can create capacity and relationship reports that include the following information:

Storage Pool Status: The condition of the resource, for example normal, warning, or error.
Storage Pool Is Detected: Shows whether the resource was detected the last time that data was collected. If this value is Yes, the resource was detected.
Storage Pool Tier Type: The type of tier that is used on the storage pool. For example, the tier type can be hard disk drive (HDD) or solid-state drive (SSD). The tier is configured to be controlled by the Easy Tier function.; This value is available only for resources that are running IBM Storage Virtualize.