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FlashArray: this is the brand new FlashArray family member – FlashArray //C - a deep dive

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

Pure Storage FlashArray //X is optimized for highest requirements in the microsecond range - Tier 1 applications - mostly business critical systems, typical examples ERP systems, CRMs and/or e.g. also mail servers... . For these systems, latencies must be avoided or kept as low as possible.

Other applications - Tier 2 - on the other hand have lower performance requirements, e.g. NAS and file data. Here it is no longer necessary to use the highest-performance technology and more expensive storage can be saved. In the past, Tier 2 storage was usually very complex to plan and cumbersome to manage. In addition, it was necessary to work on other platforms, which meant - other management platforms/APIs. So homogeneous compatibility and infrastructure is not always a given.

Even more problematic was the issue of constant performance. Tier 2 is not so "demanding" and critical, but should not be neglected in any case. Likewise, Tier 2 should also be upgradeable without interruption.

a nice pictorial comparison. FlashArray //C finds itself as a truck (lorry)

Pure Storage's answer: FlashArray //C.

With //C, Pure Storage offers high-performance, low-cost NVMe flash for all data. //C thus expands the FlashArray family alongside //X.

the FlashArray portfolio at a glance

FlashArray //C

FlashArray //C enables workload consolidation and simplification through consistent all-flash operation, while lowering total cost of ownership/TCO compared to hybrid storage.

Like all Pure Storage products, FlashArray //C integrates seamlessly with the Pure Ecosystem and Pure's "Evergreen" philosophy. NDU, Evergreen, > 99.9999% availability and Purity //FA.

The OS/Purity will not change significantly for now. The management, GUI and CLI will also be as usual. "C" also integrates with Pure1.

In short FlashArray //C is a modified FlashArray //X with lower performance, different DataPacks for less money. Flash at disk prices!

FlashArray //C Architecture

FlashArray //C is based on QLC flash memory. The latency is between 2 and 4 milliseconds. Of course, FlashArray does not use standard SSDs. Pure developed DirectFlash, which brings FTL (Flash Translation Layer) to the software. At the time DirectFlash was introduced, Pure called the hardware a "software-defined flash module," which seems contradictory. However, moving flash management to software allows the Pure operating system on FlashArray (and FlashBlade) to manage media wear and writes, which increases the life of TLC and QLC media to acceptable levels. We are talking about "QLC NVMe" at Pure!

QLC memory holds 4 bits of data, allowing it to store up to 16 states per cell. One advantage of the QLC memory is the higher storage density, which means that more data can be stored on the same chip area or, conversely, the same amount of data can be accommodated on a smaller area. This makes for lower production costs.

One disadvantage of QLC flash is that it is functionally slower than the other forms of memory in reading and writing data. Compared to SLC and MLC, lifetime of QLC is shorter, but about as long as TLC.

QLC is aimed at users who want to store a lot of files instead of HDD on SSD and rarely reads or writes these files.

Alex McMullan, international CTO, said in an interview that Pure //C will ship arrays with TLC (3bits/cell) chips until QLC chip availability is mainstream. The array software and module firmware can handle this and extend the life of the TLC module. He said customer response to //C arrays has been so positive that Pure has moved up the launch, which was originally scheduled for next year.

A Pure source revealed that the QLC DFMc's, will be available in 24 TB modules next year. This will, in turn, increase system capacity.

(a separate blog article on SCM - DirectMemory - will follow soon)

Now a few facts about the hardware. The FlashArray //C chassis is no different from the //X chassis, but different controllers are installed.

//C60 is currently the only controller type available and supports three different RAW capacity sizes: 366TB (full chassis), 878TB (chassis + shelf), 1.39PB (chassis + 2x shelves). //C60 is factory equipped with four NV-RAM modules. Also installed in the default for capacity expansion (connection of shelves) are four port 50Gb Ethernet cards "mezzanine card" (QSFP28 - QP Eth MEZZ) to connect two shelves. These modules are already known from the current //X generation for connecting DirectFlash shelves.

Unlike //X, no DataPacks can be selected. There are only fully equipped chassis and shelves with a DFMc (= DirectFlashModule)/disk size of 18.3TB. 20 DFMc's fit in the chassis and 28 DFMc's in each shelf.

a DFMc module of the //C

a DFMc module of the //C compared to the DFM module of the //X

FlashArray //C can be ordered in the basic version with Fibre Channel or iSCSI.

The FC base model has 6x 16/32G FC ports (slot 0, slot 2) and 2x 10Gb iSCSI. The iSCSI-based controllers on the other hand have 2x 10/25G iSCSI ports (slot 2) and also 2x 10Gb iSCSI onboard. The management and replication interfaces are redundant/double p. controller as usual.

//C is effectively usable at a data reduction of 5:1 up to 5.2PB

The above information/performance data is based on a status as of 2019-09-20.

Use Cases

FlashArray //C is specifically targeted at Oracle, VMware or Microsoft SQL Server instances as well as disaster recovery, archiving and test/dev applications.

What happens when you want to move data? Virtualized workloads can be managed with solutions like VMware Storage vMotion and automated with DRS and SPBM. Alternatively, Pure offers timely ActiveCluster for //C, which enables seamless migration of data between //X and //C arrays.

Replication and offloading FlashArray snapshots across multiple sites or for backup purposes could also be a use case for the new solution.

The latter makes FlashArray //C highly interesting for dev test scenarios in which large amounts of data need to be consolidated or the best performance does not play a significantly significant role.


The long-awaited unified solution with Compuverde has unfortunately not yet been released. Pure Storage believes that large customers want separate file and block arrays, while SMB customers want a unified file and block system. As of today, immediately after Pure Accelerate 2019, this will be available free of charge in 2020 as part of Evergreen as usual in a new Purity release. Compuverde is a startup that Pure acquired earlier this year.

One question that immediately came to mind was why Pure Storage decided to build its own solution for the FlashArray product family: why not a "hybrid all-flash" platform?

FlashArray///X could have easily been expanded to include QLC shelves connected via NVMe-oF. From a conversation I had, it appears that internal array tiering is not part of the Pure Storage strategy. The company believes that internal tiering solutions lead to inconsistent application performance.

There is definitely an argument to be made here between consistent performance and flexibility. In hybrid systems, there is always a risk of performance fluctuations because almost all tiering models are reactive. Implementing a single storage tier per array is one way to avoid this problem.

With FlashArray //C, Pure is making another statement. However, in my opinion, it is the large initial storage capacities in the German market that are difficult for SMBs. A 366TB RAW capacity is already a proud claim for the Tier-2 application and might be less interesting for the SME from a price point of view. I hope that //C will therefore also be available in smaller capacities in the near future.

Another shortcoming for the market will be that currently no familiar ActiveCluster with FlashArray //C is possible. "The GermanCluster" is, unlike in America, an essential part of the IT strategy of German companies. However, I was told that this is already in development and will be available soon.

Pure Storage FlashArray //C has been GA since Accelerate and is available to order now.

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

The blog lives from your questions, wishes and suggestions...every comment is welcome. I am very grateful for feedback.

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