Flash Needs a Highway


CarLights

Last week at Storage Field Day 10, I got a chance to see Pure Storage and their new FlashBlade product. Storage is an interesting creature, especially now that we’ve got flash memory technology changing the way we think about high performance. Flash transformed the industry from slow spinning gyroscopes of rust into a flat out drag race to see who could provide enough input/output operations per second (IOPS) to get to the moon and back.

Take a look at this video about the hardware architecture behind FlashBlade:

It’s pretty impressive. Very fast flash storage on blades that can outrun just about anything on the market. But this post isn’t really about storage. It’s about transport.

Life Is A Network Highway

Look at the backplane of the FlashBlade chassis. It’s not something custom or even typical for a unit like that. The key is when the presenter says that the architecture of the unit is more like a blade server chassis than a traditional SAN. In essence, Pure has taken the concept of a midplane and used it very effectively here. But their choice of midplane is interesting in this case.

Pure is using the Broadcom Trident II switch as their networking midplane for FlashBlade. That’s pretty telling from a hardware perspective. Trident II runs a large majority of switches in the market today that are merchant silicon based. They are essentially becoming the Intel of the switch market. They are supplying arms to everyone that wants to build something quickly at low cost without doing any kind of custom research and development of their own silicon manufacturing.

Using a Trident II in the backplane of the FlashBlade means that Pure evaluated all the alternatives and found that putting something merchant-based in the midplane is cost effective and provides the performance profile necessary to meet the needs of flash storage. Saturating backplanes with IOPS can be accomplished. But as we learned from Coho Data, it takes a lot of CPU horsepower to create a flash storage system that can saturate 10Gig Ethernet links.

I Am Speed

Using Trident II as a midplane or backplane for devices like this has huge implications. First and foremost, networking technology has a proven track record. If Trident II wasn’t a stable and reliable platform, no one would have used it in their products. And given that almost everyone in the networking space has a Trident platform for sale, it speaks volumes about reliability.

Second, Trident II is available. Broadcom is throwing these units off the assembly line as fast as they can. That means that there’s no worry about silicon shortages or plant shutdowns or any one of a number of things that can affect custom manufacturing. Even if a company wants to look at a custom fabrication, it could take months or even years to bring things online. By going with a reference design like Trident II, you can have your software engineers doing the hard work of building a system to support your hardware. That speeds time to market.

Third, Trident is a modular platform. That part can’t be understated even though I think it wasn’t called out very much in the presentation from Pure. By having a midplane that is built as a removable module, it’s very easy to replace it should problems arise. That’s the point of field replaceable units (FRUs). But in today’s market, it’s just as easy to create a system that can run multiple different platforms as well. The blade chassis idea extends equally to both blades and mid or backplanes.

Imagine being able to order a Tomahawk-based controller unit for FlashBlade that only requires you to swap the units at the back of the system. Now, that investment in 10Gig blade connectivity with 40Gig uplinks just became 25Gig blade connectivity with 100Gig uplinks to the network. All for the cost of two network controller blades. There may be some software that needs to be written to make the transition smooth for the consumers in the system, but the hardware is more than capable of supporting a change like that.


Tom’s Take

I was thrilled to see Pure Storage building a storage platform that tightly integrates with networking the way that FlashBlade does. This is how the networking stack is going to be completely integrated with storage and compute. We should still look at things through the lens of APIs and programmability, but making networking and consistent transport layer for all things in the datacenter is a good start.

The funny thing about making something a consistent transport layer is that by design it has to be extensible. That means more and more folks are going to be driving those pieces into the network. Software can be created on top of this common transport to differentiate, much like we’re seeing with network operating systems right now. Even Pure was able to create a different kind of transport protocol to do the heavy lifting at low latency.

It’s funny that it took a presentation from a storage company to make me see the value of the network as something agnostic. Perhaps I just needed some perspective from the other side of the fence.

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4 thoughts on “Flash Needs a Highway

  1. Pingback: The 25GbE Datacenter Pipeline | The Networking Nerd

  2. Pingback: Pure Storage's FlashBlade - Against The Grain - kamshin

  3. Pingback: Flash Needs a Highway - Tech Field Day

  4. Pingback: Storage Field Day 10 – Wrap-up and Link-o-rama | penguinpunk.net

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