Interview: ScaleFlux computational storage flash drives offer quadruple the capacity, double the performance and halve the flash costs of ordinary SSDs – so says CEO Hao Zhong.
The startup has developed its CSD 2000 series computational storage drives with on-board processing to carry out processing directly on the stored data. Over 40 data centres are working with the drives, Zhong told us in a recent interview.
The capacity increases comes from ScaleFlux compression algorithms and its way of mapping data in the drive. The second generation ScaleFlux CSD 2000 drives use an FPGA to provide the computation. ScaleFlux is developing its own Arm-powered SoC (System-on-Chip) for third generation drives. These will have much higher speed, lower power draw, lower costs, and significantly more features than ScaleFlux can fit in into the FPGA.
The gen 3 drive, possibly called a CSD3000, may arrive later in the second half of this year.
Hao Zhong: I think this is pretty simple. What do we do is we try to reduce data movement in the serve and connection fabric. So Nebulon or a DPU type of product is a good idea, however, … this will cost a lot of data movement and this means out of the gate intrusive integration for most data centre or enterprise customers to be able to use the SPU/DPU; a significant programming and software integration.
For the CSD we encapsulate all the complexity under the NVMe device protocol. So there’s no change for any application.
[See Nebulon note below.]
B&F: Is a computational storage standard coming?
Hao Zhong: There are two industry organisation are working on this. One is SNIA and the other is an NVMe one. Regarding SNIA, a working group was set up in 2018, and we were one of the founding members of that working group.
We were the first member to be able to come up with a product and start shipping from June 2019. Last year, Intel and Amazon partnered and also invested in SNIA. But for them, SNIA is a general industry standard process. Intel and AWS want to speed up the process and so they bring this to the NVMe working group.
I think that there has been significant progress made since then. Now I would say computational storage will definitely be part of any NVMe standard in the future. Computational storage will be some kind of extension of the general NVMe standard.
B&F: What partners are you working with?
Hao Zhong: We’re not only working with data centre customers, but also the server OEMs, because, you know, most of the data centres want us to quantify with server vendors, for example, HPE, Dell, Lenovo, and Inspur.
B&F: What are the benefits of using your CSD product?
Hao Zhong: Number one is the cost saving. We increase capacity by using transparent, inline compression. By doing that, we are increasing the usable capacity for customers, and we also improve the performance and the latency by reducing the number of data writes into the flash media. That’s how we significantly improve the performance and endurance.
B&F: Do you have any numbers for that?
Hao Zhong: We can improve the endurance by three to six times. The performance increase depends on whether it is a read or write. For the random read, we know we can improve the average latency, but for the random write we have from over 200 per cent to as much as 600 per cent.
If you are talking about comparing to the average SSDs – let’s say the QLC drive from Intel – they have 34,000 random write IOPS. We can pump it up to all the way to 180,000. So this is nearly six times, which is almost 600 per cent, over Intel’s drive.
B&F: There’s a difference between reads and writes?
Hao Zhong: Right, For the random read as as mentioned, there’s not much we can save because, the latency and speed is dominated by the read latency from the NAND media. But with light writes is different, because you can avoid the standard write process.
B&F: So if you increase the capacity, and you increase the performance as well, then a server could have say 10 x 15 terabyte SSD to get 150 terabytes of capacity. But if you increase the effective capacity enough that server would only need half the number of SSDs and they’d probably go faster.
Hao Zhong: Yes, right. Yes.
B&F: How do you build your CSD products?
Hao Zhong: We take a standard U.2 NVMe SSD and replace the controller chip.
B&F: Do you support the M.2 form factor
Hao Zhong: No, we’re no supporting M.2 yet, because M.2 has some limitations in terms of power consumption as well as how much footprint that we can get into this small form factor.
B&F. And ruler form factors?
Hao Zhong: Yes, we can fit in that as well. But it’s just the volume is not there yet.
B&F: Do you think that Western Digital with its zoned SSD (ZNS) idea is moving slightly towards computational storage, or do you think the zoning is so trivial from a computational point of view that it doesn’t represent any future competition?
Hao Zhong: I think they are orthogonal and also complementary to each other. Zoning space is something like the namespace that NVMe has been working on as well. So, I think computational storage can dramatically help the namespace of ZNS by providing more capacity for the user.
ScaleFlux says it provides 5:1 compression for Aerospike, 4.2:1 with MySQL and 4:1 with Oracle databases. It claims its on-board compressed flash capacity comes at less than half the cost of commodity SSDs, while performing twice as fast at writes and lasting longer.
If ScaleFlux can deliver further increases in write speed and endurance with its third generation product the attractions of its plug-and-play technology should increase further.
Nebulon CEO Siamak Nazari pointed out that, with Nebulon Cloud-Defined storage, “application, programming or software integration is … virtually non-existent,” being “equal to using a SAS array or RAID card.”