A volume is a fixed amount of storage on a storage device.

Volume properties

The name and identification of the volume. The volume name contains the user-defined name prefix and the system-defined suffix ID, for example, FBvol_00a2.
The status of the volume.
Note: If a state is displayed that requires action to return to a normal state, go to the Events page for more information.
There are no volume configuration operations in progress, and the volume is not being unconfigured, merged, or migrated. This state is the preferred state of the volume in most cases.
Data loss (pinned)
Data was lost before it was written and the track identifiers that are associated with the data are unknown. Pinned data cannot be removed from the cache by the storage machine because of a hardware failure. Overwrite or discard the pinned non-retryable tracks from the host to return the volume to a normal state.
The volume can be read but not written. Either a thin provisioned volume needs more available capacity, or an internal error occurred. Either free up space for the thin provisioned volume or contact IBM® Hardware Support.
I/O access to data on the volume was lost. Contact IBM Hardware Support.
Virtual space fault
There was not enough available space on a thin-provisioned volume to convert a virtual logical track to a real logical track. I/O access to data on the volume was lost. Contact IBM Hardware Support.
Data loss
Data was lost before it was written to the volume and the track identifiers that are associated with the data are unknown. Contact IBM Hardware Support.
The volume is being configured for the first time.
The volume is being reallocated to modify the capacity.
The volume is being deleted.
The pool that contains the volume is merging with another pool.
Provisioned capacity is either migrating to another pool or migrating within the pool.
Migration canceled
Provisioned capacity migration was canceled. Resume migration to continue migrating capacity.
Migration paused
Provisioned capacity migration is paused. Resume migration to continue migrating capacity.
Migration error
Provisioned capacity migration did not complete successfully. Resume migration to continue migrating capacity. If migration does not resume, contact IBM Hardware Support.
Configuration error
The initial configuration did not complete successfully. Delete the volume and create a new volume. If you cannot delete and re-create the volume, contact IBM Hardware Support.
Reconfiguration error
The volume reconfiguration did not complete successfully. Delete the volume and create a new volume. If you cannot delete and re-create the volume, contact IBM Hardware Support.
Deconfiguration error
A delete volume request did not complete successfully. Delete the volume. If you cannot delete the volume, contact IBM Hardware Support.
Transposition error
The volume is in a pool that did not merge successfully. Delete the volume and create a new volume. If you cannot delete and re-create the volume, contact IBM Hardware Support.
The pool where capacity is allocated for the volume.
The size of the volume.
Note: If provisioned capacity is less than 0.1 GiB (for FB) or Mod1 (for CKD), it is displayed as 0. To view additional information, select Capacity Details from the column selector in the upper right corner of the Volumes page.

The Mod1 parameter indicates the total physical repository capacity for CKD volumes in terms of cylinders. A single Mod1 unit (1.0) is equal to 1113 cylinders. 2.0 Mod1 equals 2226 cylinders.

The number of hosts that the volume is assigned to.
The volume ID.
Easy Tier®
The state of Easy Tier processing in the volume:
The volume is managed by Easy Tier.
The volume is not managed by Easy Tier.
Monitor Only
Easy Tier is monitoring the volume but will not migrate data.
Assigned to Flash
The volume is assigned to the flash tier.
Learning Paused
The process of learning about the volumes is paused.
Migration Paused
Easy Tier migrations of the volume data are paused.
Storage type
Volumes can either be fixed block (FB) or count key data (CKD). Open systems hosts such as AIX®, Windows, or Linux® use FB volumes. IBM Z hosts that are running z/OS® use CKD volumes.
Indicates whether a safeguarded backup has been configured for this volume.
Safeguarded Location
The pool where safeguarded backups are stored for this volume.
Safeguarded Virtual Capacity
The amount of provisioned capacity that is reserved for safeguarded backups for this volume.
Safeguarded Recovered
A safeguarded backup for this volume is being recovered to a recovery volume by using a FlashCopy® relationship.
Thin provisioning
Allocates provisioned capacity as needed to manage storage usage more efficiently. Physical capacity is only needed for written data; parts of the volume that are not written to do not use physical space.
Extent space efficient (ESE) thin provisioning allocates capacity in a performance efficient manner on a per extent basis in the pool or in the ESE repository. You can define CKD volumes as ESE volumes.
All provisioned capacity was allocated when the volume was created. Also referred to as standard provisioning.
Allocation method
The way that provisioned capacity is allocated within the pool.
Rotate capacity
Provisioned capacity is striped across several arrays within the pool. Rotating allocated capacity over as many arrays as possible provides optimal performance.
Rotate volumes
Provisioned capacity is allocated from one array until it is full and then continues with the next array until it is full. This method makes it easier to manage performance manually and identify bottlenecks.
Provisioned capacity is allocated by Easy Tier.
The number of arrays that the capacity from the volume is allocated on.
Logical subsystem
A logical subsystem (LSS) is associated with one or more volumes and consists of a group of up to 256 volumes.
Note: LSS is synonymous with logical control unit (LCU) and subsystem identification (SSID).
Machine type and model
The machine type and model number (MTM) that is reported for the volume on the interface type that is associated with its data type.
Data type
The data type determines the type of host access emulation that is used for the volume.
The serial number in the volume label that is assigned to the volume for use on a z/OS system.
The logical unit number reported to the host by the storage system. The host uses the LUN to identify the volume for SCSI commands.
Performance policy
The performance characteristics such as quality of service (QoS), maximum latency (in milliseconds), and priority that a volume is measured against.
Multitenancy, in storage terms, is a system architecture in which a hardware component or software application services the needs of more than one customer. Each customer is referred to as a tenant. Tenants can be given the ability to customize and run functions for defined parts of the infrastructure to which they are granted permission. This defined area is the customer's multitenancy scope. Multitenancy generally prevents a host or user from initiating a Copy Services operation that would cross the tenant’s domain boundaries.
Allocated capacity
The amount of capacity that is allocated from the pool for the volume.
Address group
The address group of the volume.
Capacity details
The capacity of a volume displays as either blocks for an FB volume or cylinders for a CKD volume.
The number of aliases that are assigned to a CKD volume. Alias volumes do not occupy storage capacity. Although they have no size, each alias volume needs an address. Alias volumes are also known as parallel access volumes (PAVs), which improve overall I/O throughput by assigning alias addresses to start additional I/O processes. This function removes the need to complete an I/O cycle before a new one is started, and also eliminates the need for queuing.