Speaking the Pure Storage terminology. The Pure Translator-'Dictionary'.

[ NOTE: machine translation with the help of DeepL translator without additional proofreading and spell checking ]

Pure Storage also has technical terms and abbreviations for its software and hardware components, which can confuse you at first. To make it a little easier for you in the future, I have summarized all common technical terms with short explanations. Once you have understood the structure of the abbreviations, you will find that they are actually very compact and easy to understand.

AC = ActiveCluster

Purity ActiveCluster is Pure Storage's synchronous mirror (active/active as a variant of replication solution) with RPO/RTO = 0 and transparent failover. An ActiveCluster volume on the cluster arrays has the same volume ID. The multipathing software on the hosts recognizes paths to both arrays and the same volume. With ActiveCluster, the volumes on both arrays are simultaneously readable and writable.

CBS = Cloud Block Store

Storage natively deployed in the cloud in the form of Purity software as a virtual appliance. Cloud Block Store allows you to seamlessly move business-critical applications to the cloud while running applications more efficiently and optimized.

ct = Controller

Abbreviation for the FlashArray Controller. Within a FlashArray chassis there are two controllers, which always operate active/active in the frontend and active/passive in the backend.

DP = DataPack

Group of at least 10x memory modules/DirectFlash modules (=DFM).

For a current list of the available DataPacks, see: FlashArray: //X Storage Configuration Matrix V2 UPDATED + NEW added //C.

DFM = DirectFlash Module

Designation for their specially developed NVMe storage modules for FlashArray //X based on TLC-NAND. DFM's are accessed via PCIe and do not use obsolete technologies (SCSI/SAS protocols, FTL, Queue). Available in module sizes: 1.1TB, 2.2TB, 4.5TB, 9.1TB, 18.3TB.

DFMc = DirectFlash Module //C

Designation for their specially developed NVMe storage modules for FlashArray //C based on QLC-NAND. DFMc's are accessed via PCIe and do not use obsolete technologies (SCSI/SAS protocols, FTL, Queue).

Available in module sizes: 24.7TB, 49TB

DFS = DirectFlash Shelf or DirectFlash Software (erroneous)

Storage expansion with a DirectFlash shelf (NVMe shelf) via RoCEv2. A DFS provides space for 28x DirectFlash modules on 3 height units.

HINT: Also erroneously used for DirectFlash software. The DirectFlash software was developed by Pure to directly address NAND memory on DFMs and to get maximum performance from the technologies. With DirectFlash software and DFMs it is possible to execute 65,536 parallel operations per Flash module.

DMM = DirectMemory Module

Memory modules for FlashArray //X70R3, //X90R3 as read cache based on Intel Optane SCM to increase performance for read-intensive workloads. Especially suitable for OLTP workloads and in-memory databases.

DR = DataReduction

Pure Storage Data reduction factor, which is achieved by deduplication and compression - without thin provisioning. This is the basis for Sizings!


Total effective usable capacity of the array after subtracting the system trim and applying the achieved data reduction factor.

Efficiency DP = Efficiency DataPack

Extended form of the DP/DataPack. A group of at least 12/14/16x memory modules/DirectFlash modules (=DFM). Can be extended to a complete DataPack by adding a conversion kit (8/6/4x DFMs).

EFM = External Fabric Module

Used as a synonym for external Fabric Module (=XFM) - see XFM. However, occasionally also used as Internal EFM (=FM).

EMEZZ = Ethernet Mezzanie

NVMe DirectFlash card for connecting DirectFlash shelves (=DFS) based on 50Gbps RoCEv2.

FA = FlashArray

Pure Storage block/unified storage solution optimized for Tier-0 and Tier-1 workloads on FlashArray //X and Tier-2 on FlashArray //C. Supports: FibreChannel, iSCSI, NVMeOF / NFS, CIFS-SMB FileServices.

FB = FlashBlade

Pure Storage scale-out file/object storage solution optimized for the highest demands of their modern workloads. Supports: NFSv3/NFSv4, CIFS-SMB, S3.

FM = Flash Module or Fabric Module (for FlashBlade)

General term for persistent memory modules in Pure Storage systems.

Or for FlashBlade:

In-chassis fabric module/controller for connection to the network with speeds of up to 8x 40G or 32x 10G.


Third instance (at Pure Storage in the form of the Pure1 cloud or on-premise) for ActiveCluster operation, often known as Quorum/Tiebreaker at other vendors.

NDU = Non-Disruptive Upgrade

Pure Storage Term for non-disruptive/performance-neutral updates/upgrades/downgrades of software and hardware.

NVRAM = non-volatile random access memory

Persistent memory that survives power failures without data loss. Flash arrays store host IOs in DDR3 RAM/NVDIMM. The NVRAM contains "super capacitors" which enable the RAM content to be written to NAND memory within the NVRAM in the event of a power failure.

POE = Purity Operating Environment

Another name for the Pure Storage operating system - see Purity for more information..

PSM = Power Supply Module

Housing within the FlashArray chassis, which carries the power supply unit. Installed in the FlashArray in two versions.

PSU = Power Supply Unit

Power supply unit within the Power Supply Module (=PSM) to which the power supply is connected. For redundancy reasons installed in double version at FlashArray and in quadruple version at FlashBlade.


Pure Storage operating system of their systems. Available in the versions: Purity FA for FlashArray (//X and //C the same), Purity FB for FlashBlade, and Cloud Block Store.

QLC = Quad-Level Cell

NAND memory cell with a higher storage density than TLC (stores four information bits per cell), but lower performance in the range of 2-4ms. This technology is installed on DirectFlash modules for FlashArray //C (=DFMc).


FlashArray generation name - Release 2/Release 3 (latest).

RA = Remote Assist

Functionality to provide Pure Storage Support with a secure direct connection to Pure customer systems when needed.


Pure Storage's proprietary RAID scheme (N+2 dual parity) used to protect against three flash failures: Device Failure, Bit Failure, Performance Variability. RAID-HA is an adaptive form of RAID that provides minimum dual parity protection, self-heals when an SSD fails or is removed, automatically increases parity protection on severely reduced data sets, and performs priority-based RAID reconstruction.


Total raw physical capacity of the storage media in the system without deducting system waste.

REPL = Replication

Abbreviation for Replications components/software functions.

SCM = Storage Class Memory

A still quite young type of memory, which in modern computer systems is positioned between volatile memory (RAM) and persistent memory (NAND) and is used in DirectMemory modules (=DMM).


SAS card for connecting SAS shelves based on 12Gbps SAS (obsolete/no longer available for new systems).

TDR = Total Data Reduction

Pure Storage Data reduction factor which is achieved by deduplication and compression - including thin provisioning.

TLC = Triple-Level Cell

NAND memory cell with a lower storage density than QLC (stores three information bits per cell), but improved performance in the range of 1-2ms. This technology is installed on DirectFlash modules for FlashArray //X (=DFM) and FlashBlade.


Raw total physical capacity of the storage media in the system after subtracting system waste without applied data reduction.

WG = Write Group

A Write Group is a DataPack (=DP) with one and the same DirectFlash modules (DFMs).

WWG = Wide-Write Group

A Wide-Write Group is defined as two DataPacks (=DP) or one Efficiency DP with the same DirectFlash Module (=DFM) capacities installed within a chassis.

XFM = external Fabric Module

Pure Storage's own switches to interconnect multi-chassis FlashBlade configurations.

Also useful might be the official Pure Storage Glossary, which is available in the Pure Technical Services Portal. Compared to this rather superficial "basic contribution", the glossary covers in-depth software-specific terminology from Pure and is aimed at Pure customers. For a general understanding of storage, we recommend the Storage Terminlogy article, which can also be found in the portal.

More info - Links

All officially published setting options in the GUI but also CLI can be read via the "on-board" user guides of the Pure Storage systems.

Click on "Help" in the Purity main menu.

The User Guide is structured like the main menu and can be opened downwards. A search function is also integrated - within here you can also search for keywords.

WEB: Pure Storage (Pure1) support portal - Ticket system and support *(requires registered FlashSystems)

PHONE: Pure Storage phone support: GER - (+49) (0)800 7239467; INTERNATIONAL - (+1) 650 7294088

WEB: Pure Storage community

WEB: Pure Storage OFFICIAL blog

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