A Closer Look at the All-Flash Isilon, aka Nitro

These days, it’s hard to be impressed by storage capacity. Every year Seagate or Western Digital rolls out a new slate of drive, each with more bits crammed onto more precisely dense platters. The emergence of flash storage didn’t seem to reignite any enthusiasm for capacity. If anything, high initial prices, the bandwidth limitations of SATA 2, and controllers designed for spinning storage made flash initially a dubious value. Now that prices have come down and the technology matured, we’ve settled into expecting progressively larger drives.

So when I read that Dell EMC was rolling out an all flash Isilon node, I initially didn’t think much. It seemed like just another inevitability on the road of technological adoption. But I’ll admit, when I saw they were offering almost 1PB of flash storage in a 4U rack, my eyes popped a little! After reading this piece by Dave Henry, my enthusiasm is somewhat tempered.

First, the 924TB node is the very highest tier they’re offering, and the delta between it and the step-up unit is pretty substantial, 732TB to be specific! And on top of that, Dell EMC mentions that 80% of storage will be available for actual utilization. It’s still a huge pool of data, but a lot farther away from that sweet 1PB figure.

On a technical level, the flash Isilon setup requires some hard decisions. It uses a custom 40GbE back-end that’s incompatible with the InfiniBand. Plus, because Dell EMC moved to journaling directly on the SSDs (instead of using NVRAM), so both the initial buy of nodes increases (3 to 4), and additional nodes need to be added in pairs. All that being said though, if you have a need for a massive amount of flash storage, there isn’t a lot of competition, especially not one with the Isilon track record.

GeekFluent comments:


First and foremost, if you’re at all familiar with the Isilon platform, you’ll have immediately noticed that the Isilon All-Flash is built on completely different hardware than existing Isilon nodes. The four nodes in a 4U form factor is a departure from providing a single node in either 2 or 4U, depending on how many drives it has.

SSDs can take up less physical space than HDDs, which is a large part of how Dell EMC is able to achieve this higher node density. Each Isilon All-Flash node is half-width and 2U in height, allowing for four nodes in 4U, in two rows of two nodes each. Each node contains 15 SSDs.


Read more at: A Closer Look at the All-Flash Isilon, aka Nitro

About the author

Rich Stroffolino

Rich has been a tech enthusiast since he first used the speech simulator on a Magnavox Odyssey². Current areas of interest include ZFS, the false hopes of memristors, and the oral history of Transmeta.

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