Reliant Technology - EMC Terms You Need to Know

When it comes to EMC, there are a lot of different terms that you may hear that you may or may not understand. We want to provide a brief overview of some of the essential EMC terms you need to know. Our hope is that understanding these terms will help you feel more empowered when talking about EMC technology.

So, what are 9 EMC terms you need to know?:



1. DAE

DAE stands for “Disk Array Enclosure.” A DAE is what houses the drives that are used in a storage array. Depending on the system and model, there are multiple DAEs available. For EMC, there are different disk DAEs for the CLARiiON, Celerra, and VNX series. Disk Array Enclosures can hold varying amounts of disk drives and can come in multiple form factors.

2. DPE

A DPE is a “Disk Processor Enclosure” and is what contains the storage processor and the first tray of disks, or “vault drives”. The DPE houses all the of the things related to block-level protocols. We suggest not to spend a ton of time messing around with the DPE - so you don’t mess up your whole system! Similar to a DPE is the SPE, or “Storage Processor Enclosure.” The SPE houses the storage processors, but unlike the DPE, does not house any disks and uses a “vault” DAE.

3. SP

The SP, or “Storage Processors,” are the controllers of an EMC array. At its most basic, SPs control the transfer of data from the server to the actual disk drives. For a VNX, SPs support block data with UltraFlex I/O technology that support iSCSI, FCoE, and Fibre Channel protocols. Additionally, Storage Processors provide access for external hosts and access for the the file side of a VNX array. For a CLARiiON system, the SPs consist of CPUs that manage the functions and memory as well as the storage system cache.

4. SPS

SPS stands for “Standby Power Supply.” A SPS is essentially a backup power supply to provide enough power to the Storage Processors in the event of a power failure. They are designed to hold enough power for the Storage Processor to ensure that any data that is in volatile memory can be written to disk. The second generation of the VNX series, or “VNX2” arrays have their own version of a SPS, known as a BBU, or “Battery Back-Up” that is installed in the DPE. The only exception is the VNX8000 array, which still uses a SPS due to higher power demands.

5. Ultraflex I/O Modules

According to Justin Paul, Ultraflex I/O Modules ares “PCIe cards that have been modified for use in a VNX system.” Depending on whether they are for Block or File use, Ultraflex I/O Modules are fitted within a metal enclosure in the back of the Storage Processors or Data Movers.

6. Unisphere

Unisphere replaced Navisphere as the management system for EMC VNX, CX4, CX3, and CX arrays. There is also a separate tool known as “USM” or Unisphere Service Manager that  provides the ability to upgrade software and firmware. If you have a support contract with EMC, you can manage your system through USM directly to upgrade, install, and maintain your software and hardware.


FAST or “Fully Automated Storage Tiering” provides high performance by automatically moving active data to higher performance storage tiers and inactive data to lower performance/high capacity storage tiers. FAST recognizes data that is accessed a lot and moves it up to higher performing disks, such as SSDs, and data that isn’t accessed as frequently will be moved to lower performing disks with higher capacity such as a SATA storage tier.

8. Storage Pool

Storage pools are the mechanism used to accomplish FAST tiering. Essentially, storage pools are capacity that is aggregated from various physical resources into a shared storage environment. Storage pools can be configured in multiple ways to make storage management more simplified and provide various benefits such as performance, management, flexibility, and higher spindle counts. With storage pools, you can have tiers of multiple different drive types in one container. So, you can have a pool with SATA drives, SAS drives, and a SSD tier. How are storage pools different from RAID groups? Read more about Storage Pools vs. RAID Groups in an article on our blog.

9. FAST Cache

FAST Cache compliments fully automated storage tiering (FAST) by allowing enterprise flash drives to be added to the array. These flash drives are then used to extend the cache capacity for reads as well as writes, meaning better performance for your array system-wide.

Want to Know More?

We hope that this article has provided some clarity into EMC terminology. But, if you want to know more, or are interested in finding an EMC solution for your data center, reach out to our EMC storage experts at 1.877.227.0828 today.