IBM FlashSystem: Capacity

The docu summarize IBM SVC/Storwize/FlashSystem capacity metric terminology and description

Table: Capacity ➡ Capacity

Name	IBM terminology (old term)	Description
Device		Storage name
Total [TiB]	Usable Capacity (physical capacity)	The amount of capacity that is provided for storing data on a system after formatting and RAID techniques are applied.
Used [TiB]	Used Capacity	The amount of usable capacity that is taken up by data or overhead capacity in a system after data reduction techniques have been applied.
Free [TiB]	Available Capacity (free capacity)	The amount of usable capacity that is not yet used in a system.
Data Reduction [ratio]		The ratio between the written capacity (logical used) and the used capacity (physical used). This ratio represents the capacity saved through the application of an algorithm (such as compression or deduplication) to the written data in a system.
Virtual Total [TiB]	Provisioned Capacity (virtual capacity)	The total capacity of all volumes in the system provisioned to connected hosts.
Oversubscr [TiB]	Overprovisioned Capacity	The total amount of capacity saved within the system. This is achieved by creating a larger capacity (so-called "provisioned capacity") in the storage system than the actual usable capacity available. This phenomenon occurs when technologies such as "thin provisioning" or data reduction methods ensure that the utilized capacity of allocated volumes is less than their total allocated capacity.

Table: Capacity ➡ Capacity Pool

Name	IBM terminology (old term)	Description
Device		Storage name
Pool		Storage Pool name
Total [TiB]	Usable Capacity (physical capacity)	The amount of capacity that is provided for storing data on a storage pool after formatting and RAID techniques are applied.
Used [TiB]	Used Capacity	The amount of usable capacity that is taken up by data or overhead capacity in a storage pool after data reduction techniques have been applied.
Free [TiB]	Available Capacity (free capacity)	The amount of usable capacity that is not yet used in a storage pool.
Data Reduction [ratio]		The ratio between the written capacity (logical used) and the used capacity (physical used). This ratio represents the capacity saved through the application of an algorithm (such as compression or deduplication) to the written data in a storage pool.
Virtual Total [TiB]	Provisioned Capacity (virtual capacity)	The total capacity of all volumes in a storage pool provisioned to connected hosts.
Oversubscr [TiB]	Overprovisioned Capacity	The total amount of capacity saved within a storage pool. This is achieved by creating a larger capacity (so-called "provisioned capacity") in a storage pool than the actual usable capacity available. This phenomenon occurs when technologies such as "thin provisioning" or data reduction methods ensure that the utilized capacity of allocated volumes is less than their total allocated capacity.

Table: Capacity ➡ Pool Logical

SVC/FlashSystem specific.

Name	IBM terminology (old term)	Description
Device		Storage name
Pool		Storage Pool name
Physical
Total [TiB]	usable capacity (physical capacity)	The amount of capacity that is provided for storing data on a storage pool after formatting and RAID techniques are applied.
Used [TiB]	used capacity	The amount of usable capacity that is taken up by data or overhead capacity in a storage pool after data reduction techniques have been applied.
Free [TiB]	available capacity (free capacity)	The amount of usable capacity that is not yet used in a storage pool.
Logical
Total [TiB]	capacity	The total amount of MDisk storage that is assigned to the storage pool.
Free [TiB]	free capacity	The amount of MDisk storage that is immediately available.
Child Pool [TiB]	child pool capacity	Indicates the total amount of space that is reserved for child pools.
Used [TiB]	real capacity	The amount of data that is stored on MDisks. Capacity of allocated extents. It includes reclaimable_capacity.
Provisioned [TiB]	Provisioned Capacity (virtual capacity)	The total capacity of all volumes in a storage pool provisioned to connected hosts.
Overprovisioned [TiB]	Overprovisioned Capacity	The total amount of capacity saved within a storage pool. This is achieved by creating a larger capacity (so-called "provisioned capacity") in a storage pool than the actual usable capacity available. This phenomenon occurs when technologies such as "thin provisioning" or data reduction methods ensure that the utilized capacity of allocated volumes is less than their total allocated capacity.
HW Compression
Active		Indicates whether hardware-compressed MDiscs are present in the storage pool.
Ratio [ratio]		The ratio between the written capacity before compression and the used capacity after compression. This ratio represents the capacity saved through the application of a hardware compression algorithm to the written data in a storage pool.
Savings [%]		The total amount of capacity saved in percent within a storage pool.
SW Compression
Active		Indicates whether any software compressed volume copies are in the storage pool.
Ratio [ratio]	Compression ratio	The ratio between the written capacity before compression and the used capacity after compression. This ratio represents the capacity saved through the application of a software compression algorithm to the written data in a storage pool.
Savings [%]	Compression Savings	The total amount of capacity saved in percent within a storage pool.
Data Deduplication
Active		Indicates that the storage pool is a data reduction pool.
Ratio [ratio]		The ratio between the written capacity before deduplication and the used capacity after deduplication. This ratio represents the capacity saved through the application of a data deduplication algorithm to the written data in a storage pool.
Savings [%]		Data deduplication capacity saving
Thin savings [%]	thin-provisioning savings	The total amount of usable capacity that is saved in a system, pool, or volume by consuming usable capacity only when needed as a result of write operations. The capacity that is saved is the difference between the provisioned capacity minus the written capacity.
Total savings [%]	Total Savings	The total amount of capacity saved in percent within a storage pool (compression, deduplication and thin provisioning).
Overallocation [%]	Overallocation	Expressed as a percentage, the ratio of the virtual_capacity value to the capacity. A storage pool overallocation of over 100 is only possible if you configure thin-provisioned volume copies.

Graphs: {STORAGE} ➡ Pool

Graph	Graph metric	IBM terminology (old term)	Description
Capacity	Total	capacity	The total amount of MDisk storage that is assigned to the storage pool.
	Free	free capacity	The amount of MDisk storage that is immediately available.
	Used	real capacity	The amount of data that is stored on MDisks. Capacity of allocated extents. It includes reclaimable_capacity.
Used	Used	real capacity	The amount of data that is stored on MDisks. Capacity of allocated extents. It includes reclaimable_capacity.
Logical Capacity	Logical Total	capacity	The total amount of MDisk storage that is assigned to the storage pool.
	Logical Free	free capacity	The amount of MDisk storage that is immediately available.
	Child Pool	child pool capacity	Indicates the total amount of space that is reserved for child pools.
	Logical Used	real capacity	The amount of data that is stored on MDisks. Capacity of allocated extents. It includes reclaimable_capacity.
Logical Used	Logical Used	real capacity	The amount of data that is stored on MDisks. Capacity of allocated extents. It includes reclaimable_capacity.
Logical Provisioned	Logical Provisioned	provisioned capacity (virtual capacity)	The total capacity of all volumes in a system pool provisioned to connected hosts.
Logical Overprovisioned	Logical Overprovisioned	overprovisioned capacity	The total amount of capacity saved within a storage pool. This is achieved by creating a larger capacity (so-called "provisioned capacity") in a storage pool than the actual usable capacity available. This phenomenon occurs when technologies such as "thin provisioning" or data reduction methods ensure that the utilized capacity of allocated volumes is less than their total allocated capacity.

Graphs: {STORAGE} ➡ Volume

Graph	Graph metric	IBM terminology (old term)	Description
Capacity	Total	Provisioned Capacity (virtual capacity)	The total capacity of all volumes to connected hosts.
	Free		The difference between the provisioned capacity and the real capacity of the volume.
	Used	real capacity	The amount of data that is stored. Capacity of allocated extents. It includes reclaimable_capacity.
Free	Free		The difference between the provisioned capacity and the real capacity of the volume.
Used	Used	real capacity	The amount of data that is stored. Capacity of allocated extents. It includes reclaimable_capacity.
Logical Capacity	Logical Provisioned	Provisioned Capacity (virtual capacity)	The total capacity of all volumes provisioned to connected hosts.
	Thin Savings	thin-provisioning savings	The total amount of usable capacity that is saved in a system, pool, or volume by consuming usable capacity only when needed as a result of write operations. The capacity that is saved is the difference between the provisioned capacity minus the written capacity.
	Logical Real	real capacity	The amount of data that is stored on MDisks. Capacity of allocated extents. It includes reclaimable_capacity.
	Before Reduction	used capacity before reduction	Used capacity before reduction
Logical Aggregated	Logical Real	real capacity	The amount of data that is stored on MDisks. Capacity of allocated extents. It includes reclaimable_capacity.
Logical Free	Logical Free	logical free capacity (GB)	Capacity of free grain blocks ready for allocation.
Logical Used	Logical Used	logical used capacity (GB)	Capacity of allocated grain blocks.
Logical Provisioned	Logical Provisioned	Provisioned Capacity (virtual capacity)	The total capacity of all volumes in a system pool provisioned to connected hosts.
Snapshot Used	Snapshot Used		Capacity allocated by snapshots.