Flash arrays are used in applications that demand increased performance with high input/output (I/O). It is often the top tier in an automated storage tiering approach. Because automated storage tiering decides where to move data based primarily on input/output activity, it does not prioritize those choices based on the individual application. That allows an SSD array to provide improved data access in an easy-to-use package.

Flash Array vs. Solid-State Array (All Flash Array)

      Flash Memory, or NAND, is a storage media designed to electronically secure binary information.  Originally developed in the 1980s, the nickname “Flash” is a reference to the memory erasure process, which to the eye looks like a “flash of a camera”.  The media is designed to be electronically erased and reprogrammed.  Flash Storage is the use of Flash Memory as a storage media primarily used for main memory, memory cards, USB flash drives and solid-state drives.

      According to Gartner’s report, Solid-State Array (SSA) is defined carefully:

1.     SSAs are scalable, dedicated, solutions based solely on solid-state semiconductor technology for data storage that cannot be configured with HDD technology at any time.

2.     As distinct from SSD-only racks within ECB storage arrays, an SSA must be a stand-alone product denoted with a specific name and model number, which typically (but not always) includes an operating system and data management software optimized for solid-state technology.

Term Definitions

Flash Memory

      Flash is non-volatile read/write semiconductor memory which is used in Solid State Storage devices. Flash stores data bits in cells. Originally Flash was designed to hold one bit per cell, which is known as Single Level Cell (SLC) Flash. Subsequent generations of Flash products were designed to hold two or more bits per cell. This is called Multi Level Cell (MLC) Flash. Of course MLC Flash is higher density memory than SLC Flash, and thus MLC Flash offers a lower cost per bit than MLC. However, MLC Flash has lower endurance than SLC Flash.

Garbage Collection

      Working in the background, Garbage Collection accumulates data blocks previously marked for deletion, performs a whole block erasure on each “garbage” block, and returns the reclaimed space for reuse by subsequent.

SSD (Solid State Drive)

      Solid state storage that may utilize traditional HDD form factors such as 3.5-inch, 2.5-inch or 1.8-inch. Solid State Drives typically use storage interfaces such as SATA, SAS, or Fibre Channel.

SSS (Solid State Storage)

      Any storage capability that is provided by non-moving memory technology rather than moving magnetic or optical media.Solid State Storage typically possesses the property of non-volatility and may take various forms such as Solid State Drives, Solid State Cards, or Solid State Modules. Typical interfaces used include SATA, SAS, Fibre Channel, or PCIe.

Throughput

      A measure of the amount of data that can be transferred from a device (reads) or transferred to a device (writes) within a specified time period, typically measured in Mega Bytes per second (MB/s). Throughput is indicative of the performance of a device in an application generating sequential reads or writes.

Wear Leveling

      A set of algorithms utilized by a Flash Controller to distribute writes and erases across Flash cells. The purpose of Wear Leveling is to delay individual cell wear-out and prolong the useful life of the Flash-based storage device.

Write Amplification

      Because a previously written NAND flash memory location must be erased before it can be re-written, the number of write operations within Flash Solid State Device typically exceeds the number of writesissued by the host. This “write amplification” can be represented in equation form: Write Amplification = (Data Written to Flash) / (Data Written by Host.)

FAQs

What is flash storage and what is it used for?

      Flash storage is any storage repository that uses flash memory. Flash memory comes in many form factors, and you probably use flash storage every day. From a single Flash chip on a simple circuit board attached to your computing device via USB to circuit boards in your phone or MP3 player, to a fully integrated “Enterprise Flash Disk” where lots of chips are attached to a circuit board in a form factor that can be used in place of a spinning disk. Flash storage is everywhere!

What is flash storage SSD?

      A “Solid State Disk” or EFD “Enterprise Flash Disk” is a fully integrated circuit board where many Flash chips are engineered to represent a single Flash disk. Primarily used to replace traditional spinning disk, SSDs are used in MP3 players, laptops, servers and enterprise storage systems.

What is the difference between flash storage and SSD?

      Flash storage is a reference to any device that can function as a storage repository. Flash storage can be a simple USB device or a fully integrated All-Flash Storage Array. SSD, “Solid State Disk” is an integrated device designed to replace spinning media, commonly used in enterprise storage arrays.

What is the difference between flash storage and traditional hard drives?

      A traditional hard drive leveraged rotating platters and heads to read data from a magnetic device, comparable to a traditional record player; while flash storage leveraged electronic media, or flash memory, to vastly improve performance. Flash eliminates rotational delay and seek time, functions that add latency to traditional storage media.

What is the difference between an all flash array and a hybrid array?

      A Hybrid Storage Array uses a combination of spinning disk drives and Flash SSDs. Along with the right software, a Hybrid Array can be configured to improve overall performance while reducing cost. An All-Flash-Array is designed to support only SSD media.

Author: Roger