The following table provides definitions for some terms used in this document.
Term | Definition |
All-flash pool | A pool which contains only flash drives. |
Block storage resources | LUNs, consistency groups and VMware VMFS datastores. |
Compression | A data-reduction method which reduces the physical amount of storage required to save a dataset. |
Consistency group | A storage instance which contains one or more LUNs within a storage system. Consistency groups help organize the storage allocated for a particular host or hosts. Data protection configurations, such as replication and snapshot settings, on a consistency group affect all the LUNs contained in the group, providing ease of management and crash consistency if the LUNs are dependent on each other. |
Data at Rest Encryption (D@RE) | The process of encrypting data and protecting it against unauthorized access unless valid keys are provided. This prevents data from being accessed and provides a mechanism to quickly crypto-erase data. |
Deduplication | A data -method which reduces the physical amount of storage required to save a data set. |
Drive extent | A portion of a drive contained within a dynamic pool. Each drive extent is used to provide usable capacity to the pool, or spare space. |
Drive partnership group | A collection of drives of the same drive type which have been combined into a hidden dynamic pool object. The drive partnership group contains a maximum of 64 drives, and is used to provide space to the pool. |
Dynamic pool | A pool type introduced in Dell UnityOS version 4.2 to provide space to storage resources. Dynamic pools allow for flexible deployment models and reduced rebuild times and flash wear compared to Traditional pools. |
Dynamic pool private RAID group | A hidden dynamic pool object created using RAID extents. A dynamic pool private LUN is created on each private RAID group, which is then used to partition space to storage resources created on the pool. |
Dynamic pool private LUN | A hidden dynamic pool object created on a dynamic pool private RAID group. The private LUN is later partitioned into 256 MB slices, which are used as the underlying storage objects for storage resources created on the pool. |
File storage resources | File systems (NFS, SMB) and VMware NFS datastores. |
Flash drive (SSD) | A flash-based storage device used to store data. |
Hybrid Pool | A Pool which does not contain only Flash Drives. A Hybrid Pool typically contains more than one type of drive technology, such as Flash, SAS, and NL-SAS. |
LUN | A block-based storage resource which a user provisions. It represents a SCSI logical unit. |
Pool | A set of drives that provide specific storage characteristics for the resources that use them, such as LUNs, VMware datastores, and file systems. |
RAID extent | An object created using drive extents to provide RAID protection for the data within the pool. Once the RAID type and stripe width (RAID width) for the pool is set, each RAID extent provides the RAID protection for the pool. As an example, if the dynamic pool is created with RAID 5 (4+1) protection, a RAID extent contains 5 drive extents to provide the 4+1 protection. |
REST API | An application programming interface (API) that utilizes familiar HTTP operations like GET, POST, and DELETE. REST architecture includes certain constraints that ensure that different implementations of REST conform to the same guiding principles, thereby allowing developers the ease of application development when working with different REST API deployments. |
Snapshot | A snapshot, also called a Dell Unity Snapshot, is a point-in-time view of a storage resource. When a snapshot is taken, the snapshot is an exact copy of the source storage resource, and shares all blocks of data with it. As data changes on the source, new blocks are allocated and written to. Snapshot technology can be used to take a snapshot of a block or file storage resource. |
Spare space extent | A drive extent reserved as spare space within the dynamic pool. Spare space extents are only utilized to replace extents on a failing or failed drive within the same drive partnership group. |
Storage resource | An addressable and configurable storage instance associated with a specific quantity of storage. LUNs, file systems, and VMware datastores constitute storage resources. |
Stripe width | The stripe width, also known as the stripe RAID width, is the number of drive extents used for the RAID type chosen for the pool. For example, a RAID 5 (4+1) RAID extent has a stripe width of 5 (4+1), and therefore contains 5 drive extents. |
Traditional pool | The pool technology available within Dell Unity systems before the dynamic pools feature was released. Traditional pools continue to be supported, and can be managed through Unisphere, Unisphere CLI, and REST API. To create a traditional pool, Unisphere CLI or REST API must be used. |
Unisphere | A web-based management environment used to create storage resources, configure and schedule protection for stored data, and manage and monitor other storage operations. |
Unisphere CLI (UEMCLI) | The command line interface (CLI) for managing Dell Unity storage systems. |