Planning for storage systems

To effectively plan your storage subsystems, you must understand the terminology.

About this task

IBM Spectrum Control uses abstract terminology, such as pools and volumes, to help you view and manage your heterogeneous storage systems. Most of these terms are derived from SMI-S, which already provides a common model for storage subsystems.

storage pool

A collection of storage capacity that provides the capacity requirements for a volume. A pool has certain storage capabilities, which indicate the range of quality of service requirements that can be applied to objects created from the pool.

primordial pool

A type of storage pool. This pool might contain unformatted, unprepared, or unassigned capacity. Storage capacity is drawn from the primordial storage pool to create concrete storage pools. The primordial storage pool aggregates storage capacity that has not been assigned to a concrete storage pool. Storage volumes are allocated from concrete storage pools. For DS8000 storage systems, the primordial pool is the disk groups or array sites that are installed in the machine but have not yet been configured into RAID arrays. Primordial pools for SAN Volume Controller or Storwize V7000 are those MDisks that are available, but have not yet been configured to any MDisk Group (one primordial pool per back-end controller). The Primordial pool for the XIV is a virtual concept that represents the aggregation of system-wide deallocated storage capacity that is available but unassigned to the XIV storage pools.

storage volumes

Allocations of storage capacity that is exposed from a system through an external interface. In SCSI terms, these storage volumes are logical units.

The following table shows the mapping of the IBM Spectrum Control terms to the device-specific terms.

IBM Spectrum Control terms:	Storage pool	Primordial pool	Storage volume	Disk
Device terms
DS8000	Extent pool	Unconfigured disk groups or array sites	Volume	Disk drive module (DDM)
SAN Volume Controller or Storwize V7000 or IBM Storage FlashSystem 7200	MDisk group	Managed disks	Volume	MDisk
XIV	Storage pool	not applicable	Volume	Disk
VMAX	Data Pool	not applicable	Volume	Disk
VNX and VNXe	Pool/RAID Group	not applicable	LUN	Disk

Many disk arrays provide an interface for the administrator to specify which initiators can access what volumes through which target ports. The effect is that the volume is only visible to SCSI commands that originate from the specified initiators through specific sets of target ports. There might also be a capability to select the SCSI Logical Unit Number as seen by an initiator through a specific set of ports. The ability to limit access is called device masking. The ability to specify the device address that is seen by particular initiators is called device mapping. For SCSI systems, these terms are known as LUN masking and LUN mapping. In IBM Spectrum Control, masking and mapping are handled through host assignment.

Note:

DS8000 storage systems track the number of spares still available after a spare disk has been used to replace a failing disk drive in the device by marking the failing drive with an operational status of "Predictive Failure." If there are not enough remaining spare disks for a rank, then the operational status of the disk also shows a status of "Error."
If a DS8000 storage system marks a disk drive with a status of "Predictive Failure" but not "Error", then IBM Spectrum Control shows a green icon with a consolidated status of "OK" in the health overlay, and does not create an alert.

IBM Spectrum Control supports IBM® and independent storage vendor systems through the native interfaces or with Storage Management Interface Specification (SMI-S) compatible interfaces. This support includes storage provisioning, asset reporting, and capacity reporting.

The following table shows the IBM storage systems that you can use, and the data sources that you can use with them:

IBM storage system	Data source
SAN Volume Controller	Native interface
DS8000® series	Native interface
XIV	Native interface
IBM Storage Accelerate	Native interface. Storage provisioning is not supported.
IBM Storage FlashSystem devices that run IBM Storage Virtualize	Native interface
IBM FlashSystem 900	Native interface. Performance monitoring and storage provisioning are not supported by the native interface. You must use SNMP to collect performance data.
IBM FlashSystem A9000	Native interface
IBM FlashSystem A9000R	Native interface
Storwize V7000	Native interface
Storwize V7000 Unified	Native interface
IBM Storage Scale	Native interface. Storage provisioning is not supported.
IBM Cloud Object Storage	Native interface. Storage provisioning is not supported.
SMI-S certified storage systems	For information about SMI-S certified storage systems, see https://www.snia.org/ctp/conforming_providers_archive.

Restriction:

A specific SAN Volume Controller system must not be managed by more than one IBM Spectrum Control server at the same time.

For the most current information about storage systems, firmware, and provider levels that are supported, see the IBM Spectrum Control support website at External link icon https://www.ibm.com/support/pages/node/388393